After a short 20 mile drive all is well, no leaks, no adverse noise.
Pondering on likely scenarios for the cause, only one springs to mind, both the diff and new oil were cold when filling.
It's always a challenge getting the bottle tube over exhaust at correct angle, then a good squeeze to get the stuff in there.
At the first signs of overflow i tend to replace the plug pronto, believing more is better, but [perhaps not.
