What a good thread, the poster asked a question and got a brilliant and concise answer to the problem in hand!
I know this is what is meant to happen but lately instead of answers OPs just get insults.
Well done Stem!
Just remember the sale of goods act regarding warranties visits etc cant really say what you need without seeing job and also you might be inclined to install it yourself
Get someone out, very common fault on that boiler, if its what im thinking would cost a call out and not much else, you cannot take the front cover off yourself so wont get much advice