Just wanted to say a big thank you to petit pablo for his advice on my boiler problems. I took your advice - contacted BG again and this time spoke to someone really helpful who sent another engineer and a manger to look at the boiler. I also got an independent in to take a look. Consensus is that the boiler might last another year or two but is badly corroded mainly due to dirty water, sludge etc. BG have offered to replace our boiler free of charge if we pay for the powerflush and magnetic cleaning 'thingy' (sorry - don't know what its called!). Seeing as they didn't fit or recommend the original boiler, nor clean the system originally, that seems a better outcome than I'd expected. They even let us choose a more expensive boiler so it fits in the original kitchen cupboard. So good customer care once I complained and started to sound like I knew what I was talking about (well, a bit - thanks Petit Pablo!).