A: I think you have answered your own question. You haven't taught for nearly 18 years and you want to change from secondary to primary in an area of the country where falling rolls and high levels of teacher retention mean that there are not enough teaching posts available to meet the number of qualified teachers looking for them.
You don't say what additional experience you have gained since 1990, but is this something that will appeal to a primary school? If not, why should they bother to even shortlist you over applications from recently trained primary teachers? If you can think of a positive answer to this question, try it out on those running the returners course before it even starts. If they are positive, go ahead. If they are only lukewarm or even negative, think again.
If you are determined to go ahead, spend some time in a primary school so that you know what you are trying to get into (if you haven't already done so). You could consider offering to work as a teaching assistant to build up experience and then use your contacts to find a school that would offer you a teaching post. You will also have to register with the General Teaching Council and consider what salary you would receive if you did secure a teaching post.
John Howson is a recruitment analyst and visiting professor of education at Oxford Brookes University. To ask him a question, email him at firstname.lastname@example.org.