Thanks for help and tips, got a qualified gas safe engineer to check it out, it seems it was the gas ignite contact that had closed up, he was able to re-gap it without breaking it, so all is now well and don't feel nervous anymore :)
Hi All
My minimiser s.e. ff50 is giving a big bang when igniting, some time it takes three attempts and bangs before firing up.
The boiler is serviced annually and has only recently been done.
What is the problem and am I right to feel nervous about this bang