No grants currently available for alternative fuels in vehicles whenther business or private.

If yours is a company car I'm not sure if your BiK will go down after you fit an aftermarket LPG kit - I suspect not.

If it is a leased car, the owners may not be happy about you fitting an aftermarket kit - best get their OK in writing before spending any money.

Similarly, not sure what the script will be with your London Congestion charge - it would be too easy for folks to stick an extra fuel cap on the wing and tell TFL the car has been converted!!!

And unless the law has changed, forget about taking your car through the Channel Tunnel (or any of the major UK tunnels) - don't know why, but the gas tanks weren't/aren't legal in there!!