getting british gas out to do this would be agood idea but i would go for the contract, over the one off visit, we have alot of these on the patch i work on in the south west, they are very prone to leaks, and highly prone to breakdowns the company was bought out by ariston a couple of years ago, they have subsiquently removed chaffoteaux boilers from sale in the UK, only thier very sucsefull water heaters remain. so you may end up having BG out more than once a year, so a contract would be best for you.
Mark, February 2007