4cyl or 6cyl?
If you want a Perentie winch I'd be looking at a wreck from graysonline, give it a few more auctions and you'll get the complete winch for a fair price and a few spare parts wrapped around it!
Looking at Wayne's winch the rear shaft looks shorter than the front shaft so it would be off a 2 1/4 motor. typically Thomas winches where fitted to series 2 and 2A civilian but also army sometimes, Bamford where fitted to 2A and S3 (2.6lt motor)
This is off a military vehicle as it still has the brush bar supports attached.
So my guess, it would fit straight onto a 2A military 4 cylinder
Cheers
Scott