Thank. My new shafts arrived today and I can confirm they are the new ones.
I won't be building it until boxing day but I can't wait now.
Might try and pick up a few hop ups in the mean time if I get any spare cash.
I've got a tube of green slime so I'll bang a load of that on around all the o rings while I'm building the rear diff.
Tbh it's not a huge issue as long as it doesn't dump all the oil in one go, diff looks easy enough to get at and rebuild anyway.