Biasi Advance + 35C Boiler

I should have listened to all the negative advice about BIASI boilers but I went ahead and had a BIASI boiler fitted. Within weeks began having problems with taps/shower running hot/cold, boiler leaking & losing pressure. Five visits within 9 months and several parts replaced has resulted in a £95 call out charge from BIASI and the remainder of my 5 year warranty (4 years left) suspended until the bill is paid. Biasi claims that the problem isn't due to manufacturing problem but due to dirt in the system blocking the heat exchanger, even though their installation benchmark was carried out to the letter. It's an intermittent fault and boiler been working ok for last month but I could not recommend BIASI to anyone. It has to be the worst customer service I've uncounted and this must be the worst boiler I've ever had fitted. Stay away from Biasi, learn from my mistakes.