Since there is still a considerable shortage of teachers in the UK, local schools are keen to employ experienced former teachers to return to the classroom, even if it is only for one day a week.
Working for an agency does not necessarily affect your Teacher's Pension Allowance, this is usually only affected if you work for the local authority.

At S.A.S. Teachers we offer a flexible, no pressure service, finding you work on the days you want to work, in the schools where you want to work.