Over the past week, I've managed to get some long awaited jobs done on the car.
Coil pack changed for new item. Old one was breaking down on cylinder 1 and 4. Plug 1's ceramic had cracked. Plug 4's centre electrode had blown away

All 6 plugs replaced with VX items.
A good set of VX HT leads fitted (thanks to lincs rob for them)
ICV replaced with known good spare (I dropped the other tinker and it started to rattle

)
Right put it all back together, turned the key and it fires first time and runs very smooth.
Here's the problem ............... No matter what the engine / coolant temperature is, the idle will not drop below 900 rpm and the inst fuel reading on the mid will not drop below 0.6 ltr/hour

This is the same whether it is running on petrol or lpg.
I'm 99% sure there are no airleaks.
I have blanked off the small pipe from the bagpipes to the icv and the engine stalls instantly.
I have also had a spray around with carb cleaner around the normal spots to see if the revs rise with no luck.
It would seem that the engine is airtight in all the right places.
The Icv and the throttle body are spotless as are the breathers.
I have had my "My Naff Code Reader" plugged in to check the lambda sensor. Both are switching between 0 ish and about 900.
Why the hell won't the revs drop at idle ?