Thanks for the reply Geoff - I managed to replace the driver's side outer hub seal at the weekend with not much fuss. The passenger side proved impossible so I left it as it doesn't appear to be leaking anyway.
I think there's a lot to be said for the driveshafts bending as I'm using much stickier tyres this year and the problem is much worse since I've started using them...
The stud back plate was full of oil which would spin out eventually into the hub so I disassembled it, cleaned it and sealed it before resembling...
Whilst I was at it, as the seals have a spring inside them, like with the crankshaft oil seal on the back of the engine, I unscrewed it and removed a few mm to make it a bit tighter.
Everything went back together beautifully and it was quite an enjoyable job.
As I said, the other side proved impossible and fearing damaging anything gave up before I reached an irreversible situation!