That's excellent news Phil thanks for the reply i have found one on eBay for 25 quid so it's worth a try then if not think next step is to get the transfer box o r and have a look inside
many thanks again

Hi all just thought I would post an update, I fitted second hand Ecu and exactly the same really it will engage gears for a while then just loses drive I did notice a grating kind of noise when selecting both reverse and drive which stayed there while in gear.
Anyway pulled the oil pan off and the oil was absolutely black there was lots of gold and silver filings in the oil and the magnet in the sump was full probably 4 my thick with what looks like sludgey swarf so I think I’m looking at the box is knackered going to have to have a think if going to sell as spares or repair or get the box out and have it rebuilt