NEW homes for teachers are being built on the site of a former primary school in north-west London. Acton Housing Association is building 152 homes in Northolt on the site of the former Willow Tree primary school, which has moved to a new building next door. Of the 152 one and two-bedroom flats, which are due to be finished in autumn 2003, 76 will be for sale, 54 for rent and 22 for sale to teachers through a shared ownership scheme with the housing association.