Lpg when switched on cuts out

Hi everyone, looking for some guidance and help. My discovery 1 es v8 with lpg conversion has always been sweet till I removed the side mounted under slung tanks . The pipe work was blanked off and sealed, every thing looked sweet (no leaks) now when I try to switch from petrol she cuts out and won't run on gas
Have I missed something? And yes before any one asks I did turn the tordial tank back on.
Really had me scratching my head,
My thoughts are maybe not warm enough to switch over?
She used to start on gas before tanks removed
Would I benefit from having the system serviced
Like I said earlier , it's making my head hurts lol
Hope you can guide me with all your combined knowledges

PS
It's an emmegas single point system

When you took the tanks off had you fully emptied them as a precaution. If so and you returned them back on did you fill to a small amount to purge and reset. You may have picked up dirt inside the tanks that cutting the flow. On the leak tests do you have gauges to show gas in tanks. As a safety matter I would make sure the petrol side works perfect and then consult a registered LPG garage for help restoring the balance. Also does the LPG rely on the exhaust sensor

Left the tanks off, risk of getting mullered when going off road, before sealing I switched gas on to purge any crappy out of system. The petrol side of things work as normal , so I think serviceing is the way to go. Plus that will give peace of mind.
Not sure previous owner had it done. It's taken me a year getting her off road ready and found quite a few raised eyebrow bodge it's which made my skin crawl lol
I knew I had a few things to do before I bought her, but the chassis and engine were solid (no rust, no oil burning or knocks or rumbles

Does the electric solenoid valve on the toroidal tank work when you switch to LPG?

Is there some sort of excess flow valve that needs resetting, if it has tripped when you purged the system to quick?
I believe some auto reset but some need manually reset.

They are a safety a device if you break a line in the system and would be very close to tank.

J

Hi guys, found the problem (thank god) there was a break in the wiring going to the tank solenoid, so thanks ratae and maroon, your advice led me to the problem.
So big thanks guys