If you have a fault with any WB boiler and you are worried about paying a heating engineer the hourly rate + parts (- which is a reasonable thing to worry about, esp if you watch rogue Traders, etc)...
Then just call out WB - their engineer will (almost certainly) be able to fix it and have parts on his van.
You will pay one fixed fee, no matter how long it takes and no matter how many parts and the work will be guaranteed.
I haven't called them lately myself but I think their charge is about £275 including all parts and labour, somthing like that so do check with them not me - but it is a good deal.
NOW - what annoys me is when people tell me they think WB are too expensive so they are calling around local engineers hoping to get the work done cheaper!
Actually I as just looking through some old stuff and found some figures from a newspaper survey (was it which)
it had the average boiler repair including parts at about £450.
**** Edited to add - in case it is not obvious - I do think it is best to build up a good relationship with local Gas Engineer & Plumber - but if you don't have that to rely on and are worried about being ripped off....*****