Looking at putting the Lane on LPG and just wondering whether a 6 cyl setup will suit or not?? If not whats the rough price on a new system??

Not sure about the 6cyl system, but I paid about $2,800 a couple of years ago for a new system for my Lane. Got the $2k grant from the gov't, so all up $800 out of pocket.
I have heard that the grant has been reduced or even axed entirely. Not all bad, the install price will probably come back to respectable price without the grant feeding the greedy pricks pockets

The rebate is $1500 at the moment I think. I think there may be one more drop then it may be gone after that.

I think you should be able to use all of your kit except maybe the mixer ring. It may have to be specific to the 5L.

Have a look at a few of the ebay LPG injection kits. A few choices there too with much better performance.