I have been using advanced now for many years and would never go anywhere else. Baxi genuine parts supply genuine parts and spares for all potterton boilers. Before you commit to chemicals, however. Kurt is one of the most proficient and personable plumbers i have ever dealt with. For a quick and easy fix for your blocked drains, try pouring a pot of boiling water into the drain in many cases, this is enough to loosen or dissolve the blockage without.