I have a Trianco Homeflame gas fire/boiler.The boiler works fine but I
can't get the fire to stay lit. If you turn the knob on the top and
press the ignit button it lights okay but when you then release the
knob after 30 seconds to turn it on properly the gas stops and the
flame goes back out.I had this unit serviced 6 months ago and this is
the first time I have tried to use the fire since then. Is there a
setting that might need to be adjusted? Any help would be appreciated.

Borosteve.

Sounds like you're in UK. I'm not, but what I can see from here is
that the pilot is either not heating its "sensor" or the valve is
failing-safe.

Likely needs service/parts. Not the sort of thing to muck about with.

J