I still have gas in bottle (although it must be down) as it runs a weber BBQ.
The gas cookers on stove in van will only run 1 at a time & then not flat out. It has done it before & then come good. Is it a blockage or the regulater?The tap in line is full on. any ideas? I am nowhere near a gas fitter

It could be the regulator and/orgunk in the hoses from the cylinder to the regulator.
Check that the inside of the hoses are nice and clean.
If they are then it's an even money chance that it's the regulator.
If the hoses have gunk in them, then so to will the regualor and all will need to be replaced.
Note: The inlet of the regulator should be higher than the outlet of the LPG cylinder.
Many van builders still fail this basic installation proceedure. 
Cheers, ozjohn. 

Thank you Ozjohn. The regulater is below the bottle outlet ( good on you Coromal)
  I will pull the hose off & check it. I will prob need an extension pipe to lift regulater when I can get one. There is a small screw below the regulater in the line at the join that looks like it mite be some sort of an adjustment???Have you any idea what this might be?

My Old reg had a pressure adjustment, new one hasnt. Dont play with it. First thing I would do is fill the gas bottle
cheers
blaze

If your webber runs from this bottle & regulator ok , then that proves that the reg & bottle are ok,
Each control knob on the stove will have a very small jet in the back of each control unit. these can block with a black tar like substance , resedue from gas, these jets can be removed & cleaned, some times needing  solvent to disolve the blockage.

I've done this many times with camp stoves, there's a product called brakeclean , from auto outlets , used for cleaning oil/grease from brake components[pressure pack].
its a hydrocarbon & workes very well.

The can should have a small plastic tube supplied with it, tapped to the side of can,
fit this to nossle of can & other end into the jet, the blast will help clean & blow debries out.

TURN GAS OFF FIRST. 

I thought a weber run an unregulated system with very small hole in jet whereas the caravan would run the regulated system with much larger holes in the cooker cheers blaze

I pulled the regulater off & there is black gunk in the line below where it was. Guess this is becos the reg is below the gas bottle outlet??Maybe when I am near a compressor I could break the line at oven & blow it back( by the way the hot water still works OK ) havnt tried the behind the control one yet but suspect it would have gunk as its in the line. At the moment I can get 4 burners to light but have to turn 3 off to allow the fourth to cook with enuff flame

Deefanow,
After having similar problems I had the regulator replaced under warranty after a small convincing discussion. Sometime later, I happened to be somewhere and eavesdropping a conversation, the following was mentioned.
Camec were replacing a lot of regulator for no apparent reason. Someone decided to investigate and found rubber duct in the regulator that caused the blockage. This is where it gets interesting. This chap at Camec concluded that there is/was a chemical substance in the gas that caused the rubber from the hose to come away. At this point the jury is out in terms of is it the rubber hose causing the problem or the chemical affecting the rubber hose?
The quick and permanent fix is to replace the rubber hoses with a copper pipe shaped in a pig tail. This is the way it used to be.
As always, I stand corrected
Larry

This is a very old thread and no doubt the OP has sorted out the problem..

Untill today last post Feb 27 2011....