I've been uming and aring about installing a trip compiuter for quite a while in my car as I figured it was a waste of time and money as it wouldn't work with my LPG, but turns out it does, shows it all when driving on LPG!

lol..

guess what! so does mine! and has been for a few years lol

Provided you have a changeover relay to swap the LPG/Petrol fuel tank sender input to the instrument cluster fuel gauge, all non tickford LPG setups will work. Your LPG fuel sender needs to be compatible with the Fuel gauge as well. The trip computer still sees the injector pulse width, but of course the outputs to the injectors are open cct during LPG operation. On the other hand, being integrated, a Tickford LPG setup disables the injectors at the ECU, so the trip computer won't show any data on LPG operation.
Nonetheless, I've found the LPG data to be reasonably accurate, and obviously this can be compared with successive LPG tank fills.
TWR, if your wagon runs the '3 diving tanks' LPG tank, you'll find the fuel level varies all the time, due to the sender being in 1 of the 3 tanks, so the trip computer data won't be accurate most of the time.

So the info my trip comp is showing is accurate even on LPG?

I have nothing to compare it with to test the accuracy!
But I'm happy that it works.

is that with the stock tickford system ????

Most definately not, the mechanic says it definately on at least it's 3rd LPG system already, and it's a Parnell.