potterton neta heat 10/16?

The B gas engineer says thatour boiler is beyond economical repair i.e the part that requires replacement is grommet seal they would not give me the part number is this true? they say that even if it is fixed it will not be safe, although they have issued safety certs for the last 20years, how can it suddenly become unsafe? i feel they are only interested in getting us to install a new boiler. Last week the boiler was working perfectly. the problem that arose is that it stopped ignigiting when switched on,