Well I must have screwed up - it’s a good thing there was a leak and I discovered it before the rear end was installed- 3 or 4 nuts at the bottom were still loose - not completed torqued. It’s fixed now!
if you're anything like me it only takes a phone call that takes a while or a 'dinner's ready' call from indoors and you can forget where you're at quite easily. glad you caught it.
neil.