Well another day of rookie mistakes!!!
So I found out the hard way that the rear diff from a series 2a LWB is different to a series 2 SWB.... Spring mounts are all different. Of course I found out after I'd removed the old one and tried to fit the new one... Measure it up next time I hear you say...
Oh well... So if there is old oil and crud in the drums is the a good sign that the seal between the diff and brake is gone? Looks like I'll rebuild the old one.

