PAYE employees can't get away with much when it comes to tax deductions. The principal ones for teachers (which are automatically accepted) are 'professional memberships'. When I was teaching, I successfully claimed my union membership fees (P.A.T.), and my membership fees for the Mathematical Association, the Association of Teachers of Mathematics, the Institute of Mathematics & its Applications and the College of Preceptors. However, my claims for such things as 'essential replacements of tools of my trade' (e.g. a new scientific calculator) were always ignored.
Chris