In hind-site this thread could have gone very differently, along the lines of...
OP Q1) Hello, my boiler has been making a bit of a banging noise at the end of each heat cycle for a little while. It is now making what I'd describe as a groaning noise shortly after firing, progressing to more of a vibration later in the heat cycle.
I attempted to take the cover off several years ago because I wanted to try and get the vacuum in there to give it a clean out, but it seemed a bit impenetrable so I backed out.
I'd like to give it another go now, otherwise I see a repair bill arriving!
I've googled for some dismantling instructions before but didn't find anything. Could someone please help.
Many Thanks
A1) The process of removing the outer covers and inner sealing panel is very straightforward, just a few screws. Trying to do any more dismantling to clean the burner assembly is a lot more involved and is only the job of an RGI as you need to disturb the gas supply.
There is a very good chance that if the boiler has not been serviced for 7 years there will be damage to key components of the boiler some of which are very expensive to replace.
As an insurance policy I would suggest you contact the approved service company for your Ideal boiler and request a "fix cost repair", that way you should be covered for any eventualities as to the cause of the symptoms you describe.
end of answer
I would be in a very different situation now.