Mark replaced the toilet valve very easily, quickly, so flush no longer makes an awful noise. I was highly impressed with the efficiency, thorough, Clean, and Service of my Baxi Boiler, adhering and above Gas Safe Standards. Mark also carried out Flu Analysing Performance Electronic Test of The Boiler all inclusive the clean, service ,and it matched up well to my boilers manual factory settings safety requirements. He also is very professional with his website, electronic receipts and gas certs, and is highly professional and very friendly, and offers the best value price too. He is based in Welwyn Garden City which is perfect for me.