Anyone know a UK stockist for Twyford cistern washers for a 40 year old Twyford cistern (for the top of the porcelain dome). I recorded the number stamped on the porcelain for the unit but cannot find any suppliers (and Twyfords don't stock them either!). Bodged a replacement which failed after 2 months! It is a collar washer to fit a hole about 1/2" diam, with a collar above of about 3/4" diam, through which slides the shaft attached to the 'plunger' (not sure of the correct terms!). Thanks