cut out

new range rover convert here needs help bmw 2.5 turbo diesel cut out when idling revs at about 650 ok when foot on accelerater and revs about 750

Welcome to the Forum, check all the earth straps for breakages, Bazz.

Is it a manual?

no automatic

How much fuel is in the tank? Does it run normally at all other engine speeds? How does it start from cold and hot?

full tank drives lovely but cuts out when revs drop to about 500

The problem is causing the idle speed to drop to 500 rpm, it should idle at 750rpm normally.

So what could that be? Have you checked all the intake hoses, could be a collapsed hose restricting air flow, or the air filter even.

After that you are looking at electrical gremlins which are harder to diagnose/fix.