I've had exactly the same issue first time out in new Swift Challenger. Arrived at Rowntree Park with sparkly new van, decided it was time to cook the mega pizza we had taken with us. Try as I might, couldn't get the oven to light. In the end, my temper took over, pizza went in dustbin, uncooked. All sorts of threats were made in front of cowering wife to ring dealer first thing in the morning and make him come to York and sort out duff van/cooker. Vented my frustration on chap in next pitch who smiled and suggested closing hob glass, leaving for two minutes, opening hob lid again FULLY and try again. Five minutes later sheepishly fumbling around in dustbin to retrieve pizza and cook in now hot oven!
However, if your problem is no gas appliences working, I would suggest disconecting the hose from your regulator and fitting the regulator back on the gas bottle. Then quickly open and close the valve on the regulator. If no gas comes out, go and spend