Having done some searching, this PCB issue appears to be widespread on Potterton suprima boilers - I called Heatteam on 08706096096 - they are the official service engineers for this boiler. If you explain that you are aware the PCB problem is reoccurring and that it was featured on Watchdog earlier in 2007, they will send an engineer FOC and replace PCB for free. An alternative is to pay £300 (in installments) for 12 months of parts and labour cover.