Austarion

Right so externally I know you can't tell the difference externally between a lsd and non lsd diff, but are there any differences apart from the size, visually between the large and small diffs?
I remember something about where you fill the diffs with oil are in different places?
Can anyone tell me the lengths of the torque tubes for large and small diffs?

Thanks for that. So they're almost identical.
Could you do me a huge favour and measure both diffs and torque tubes end to end?
Probably going to be the easiest way to tell them apart.

Nope, sorry, I took those photos a couple of years ago and now I've sold the small diff and the large diff is in the car. I'm pretty sure I posted all the measurements on here back then though, so do a search and you'll probably find it.

On a small diff, the area where the drain bung is, is more pronounced

Is the small diff is shorter, and thus has the longer torque tube?

yep!