OK Thanks for the help Lads,
New manual hubs for the F75 are available from http://www.ks-international.com/product_detail.php?pid=MjkzNw==&mcat=NDc=&catid=NjYw
if anyone is interesded for about £100.
Now I needed to get this old tub up and running today so I have stripped the auto hubs that were not working and welded them up. I don't know how to put pictures on here but if anyone wants some to see what is done and what part to weld then just email me and I'll send you a ZIP folder .......It's an easy job taking only 30 minutes a side and everything is working fine and with the open front diff 4 wheel drive is engaged by the button on the dash for high range. I don't use it for long journeys so don't expect to notice the slight difference in MPG that I might lose!.....hey I've just saved £100 so there is a smile back on my face.