The booster is a mains powered one

I put a cable from the starter motor to the battery negative to try earth it and see if the starters earth was **** but it made no difference

The starter motor was swapped from a working engine so could there be anything else to try

The starter isn't turning the engine over all it is doing it engaging to the fly wheel and nothing else I put a battery booster on to make sure it had enough power I've put a supply straight from battery to the starter to check of there is supply getting to it but that makes no difference...

Checked the feed and the starter engages but nothing else happens what's the best way to check if its getting a supply

I should have really thought out a reply before saying something abut simple like I did, having one of them off days where u can't think of the most simple of things

Its a twin battery set up but i believe both batteries are Oki

What's the best way for me to check

Currently have problems with a land rover discovery 300tdi, when turning the key all the dash lights aluminate as they should do but when turning the key to start the truck nothing happens. The engine doesn't crank or nothing. The truck can be bump started but not started off the key it has a...