firstly, the 'workman' from the local council needs to be a corgi registered installer to do anything of the sort with your boiler (and does he have suitable insurance to do this job for you? I hope so!)
A boilers lifespan is usually 10-15 years, as this is a 17 year old boiler, I would recommend fitting a new one (perhaps the Baxi Solo HE, save you 10-15% on your yearly gas bill too!, not too mention the environment)
T, July 2008