gas fire

[shades]

can't get my valour gas fire once ignited to stay on ..it keeps cutting out

[Mortartube]

I would suggest that you get it serviced. It may have a safety cut out that's keeps tripping because something is wrong.

[BillyBB]

It does sound like a faulty thermocouple. Get it serviced by an accredited professional. These things can produce carbon monoxide, colourless, odourless and deadly.