In a statement to TES Scotland, the Minister has some positive comments to make on the mixed age group classes. He says: "Composite classes are fairly common today and can allow the formation of smaller groups for certain activities which is of benefit to pupils and teachers. Provided sensible use is made of groups and individual teaching methods, children can and do perform well under these arrangements. "
He points out that any alteration to class sizes will require a deal between unions and employers in the Scottish Joint Negotiating Committee. As for cutting straight class sizes, a joint Convention of Scottish Local Authorities and Scottish Office working party is currently costing this.
Calling for the removal of the 25 limit in composites to produce a flat rate of 30 for all classes, Clackmannanshire education director Keir Bloomer reasons that that is how to make "best use" of the multi-million pound pot of money to cut class sizes in the early years.
He says: "It would be a great pity if we took the first genuine pot of new money and essentially frittered it. Class size makes a lot of difference in the early stages only if the drop in numbers is significant."
His first preference is for Mr Wilson to be flexible on the 30 limit. But observers doubt whether Downing Street will permit this, since the pledge of 30 was such a prominent part of the general election campaign, and assertions that manifesto commitments are being delivered are a key theme of the new Government.
Mr Bloomer argues that slotting in up to five extra children would have little impact on a composite class, since even an ordinary class has a wide spread of ability. And creating one larger-than-usual composite would help prevent extra composite classes up and down the school. Money could then be freed for more focused measures to help P1-3, such as home visits, co-operative reading and extra nursery nurses. It could also fund auxiliary help in composites over 25.
Mr Bloomer concedes that parents are not keen on composites. "They think they will not help close the gap between children's ability and attainment.But all classes are composite anyway. Age isn't even the most important determinant of a child's attainment.
"Parents would have to be persuaded that it is to their children's educational advantage. It is more important to reduce the number of composite classes than to reduce the number in it. But in the end, the parents are the customers whether you agree with their opinion or not."
Commenting on the director's proposal, assistant secretary for the Educational Institute of Scotland Ken Wimbor welcomes the planned reduction of straight classes to 30. "But I don't see why teachers and parents should be obliged to trade off one limit for another. It would be like robbing Peter to pay Paul. In smaller classes there is more time to devote to an individual."
The union's long-term aim is for primary classes to be no more than 25 and for P1 and composite classes to be even lower. Asked for his reaction to the director's proposal, a Scottish education official who declined to be identified whistled in wonder. "Very interesting but I can't see teachers agreeing."
Aberdeen education director John Stodter rejects the notion of enlarged composites as a way of coping with the repercussions of ordinary class size reduction. "It is not in the educational interest of the child. This erodes a basic principle and is a dangerous route to go down. It is difficult enough managing different levels of ability. The issue for the teacher is giving individual attention."
Composite classes are always a contentious issue, but teachers are surprisingly keen on them. John Nethercott, headteacher of Aviemore primary in the Highlands, which has three composite classes, says: "It is important that sizes of composite classes are kept as small as possible.
"In the urban schools parents can be anxious perceiving that children might be kept back or not be able to keep up, but their fears aren't justified. A teacher takes every child where they are and moves them on."
Helen Cunningham is a teaching head of 43-pupil Muckhart primary in an idyllic country setting by Kinross. Composite classes are the norm in rural areas. "It's not an issue at all," she says. "Children work hard at their own level and there is a nice family atmosphere."
But Mrs Cunningham, who has 22 pupils in her P1-3 class, concedes: "It is hard making composites work. There can be a huge range of ability, so there is an awful lot of preparation." Much of the work stems from her unwillingness to have mixed year groups for many activities, in order to protect the self-esteem of older children if some younger children are very able. If a young sibling is more able than an older sibling at maths, the teacher puts them on different maths schemes so that their different levels are disguised.
Children learn tables and phonics together. "P1 can be a bit mystified, but they are quite keen to learn. And basic work acts as reinforcement for older pupils."
Mrs Cunningham uses her entitlement of two days of headteacher relief to employ specialist teachers to support the curriculum and allow her to focus on particular work with year groups. She does admin in her own free time at home. In the classroom she has strategies to occupy one ability group usefully, while she gets teaching time with another.
Children might be invited to make a basket out of plasticine and fill it with three oranges and five pears, while she listens to older children read. In dealing with so many ability groups and different spans of concentration, Mrs Cunningham compares herself to a juggler and says she does not find it difficult. But she did once come back to her room to find a supply teacher very stressed.
About the possibility of larger composite classes, Mrs Cunningham says: "I would find that harder and I wouldn't get to know the children so well, but the same strategies would apply. "
Anne Pearson, headteacher of Park primary in Alloa, says that the frequent need to break up composites and form different composites in later years is the problem. "Children get a sense of security and an identity from their class. It can be like a divorce when it breaks up.
"Parents can be unhappy too. They might say: 'OK, we'll tolerate it like this for a year, but not again.' But I can't give them that reassurance."
Stressing that composite classes seem to have worked well in the school, Mrs Pearson says: "I'm not sure that composites are a bad thing, but they're not milk and honey either. There's a big difference between a five-year-old and a seven-year-old and what they're interested in."
Probationer Rosalynn Rennie, in charge of the P2-3 composite at Park, describes composite teaching as "definitely more difficult". She has six language groups and four number groups in a class of 21 and finding something that appeals to the two-year spread is tricky. But there are advantages too: "P2s can see where they will be in a year's time and it motivates them. They get to mix with different ages and P3s help the younger ones with things like getting ready for gym."