Boiler Flame making loud roaring noise

[FabianTraybender99]

It appeared not to want to switch off after moving the time to the off position.

Fair enough now OP has come back and explained, but the original post that i replied to was about why it didn't switch off with timer which now probably is not the problem.

It still would not switch off at the timer

 

[waterworks]

Then i would say get the rest of your system checked as well as the boiler because you may well still have a sticking valve.

 

[mogget]

Waterworks, would you like a spade

 

[namsag]

I would agree with you water works the motorised valve microswitch is probably also stuck and that fault has not shown up untill the gas valve or whatever has caused the injector to back light.
A severely knacksed gas valve will stay on high even after power is off but the give away is the OP said on turning boiler stat down it goes off which would fit in with icroswitch also stuck