Hi All, here's a followup...

Ed Sirrett...
Possible causes a
Damage to the oxy pilot assembly - however the should be vertical.
Partially blocked pilot injector.
In adequate inlet working gas pressure - should be at least 18.5 mBar.

BG came round today to service the boiler (which they still haven't
fixed the faulty diverter valve I had pointed out to them but I don't
have time for that today)..

I got one of them to have a quick look at the gas fire (which now has
a yellow 'at risk' label attached to it). The first thing he said
before was that I need an air vent (100cm2) because it's a DFE. If
it's an inset living flame fire under 7KW then an air brick isn't
necessary - so I take it I should get this done quick sharp?

He quoted me £66 to supply and fit the air brick, is that reasonable
or do you think I/someone else could do it for less (and easier)?

After 2 years of using it 'at risk' there must be something else
causing it to cut out, so I asked him about the pressure. He didn't
measure anything because he wasn't there to look at the fire, but his
opinion was that the pressure is fine and the draw up the flue was
perfectly adequate as the flames were roaring up there.

What he did point out was that the flame from the pilot should
envelope the thermocouple but it wasn't, so he suggested there may be
some crap in the pilot jet, and I should get it serviced for around
£60.

What do you reckon?

Stu.