GQ TB42EFI Dual Fuel will no longer start on LPG when cold or left overnight

[aflman]

Hi all,
I have a mid 90's GQ TB42EFI Patrol on dual fuel that always started fine on gas and petrol. I normally leave the switch on the gas position as it is an Impco system that starts on petrol then switches to gas.
In the last week, first thing in the morning or if I've left it for most of the day parked, it would start on gas but then die a few seconds later. Has never done this before. So, I would put the switch to the bottom petrol position and it starts ok and then when warmed up, I would flick the switch back to gas by raising the revs to around 1500rpm and it then runs fine on gas as it always has and starts on gas no problem again if I am using it during the day.
However, next morning it does the same thing of starting momentarily and then turning off a few seconds later. Today it would not start on gas at all but when I switched to petrol and let it warm up and repeat the above, all is good again.

Anyone know why this is happening thanks?

The lpg installer I had who did this conversion a while back is no longer is around but I noticed they bypassed the solenoid attached to the Converter (as in the pictures attached) and there is only one wire coming from under the dash that goes to a possible second solenoid behind it that the gas hose is attached to (as in pic). The other wiring loom from the back of the dash switch goes to the PEEL CP30 Safety Switch.
I cleaned the terminal connections and earth wires up since the pics but no difference noted.