LSD problem? Help would be appreciated!

[RMW50]

Firstly can I say that I am no mechanic, so please excuse the lack of technical know how!!

Driving the toy the other day there was a really strong smell, first I though brakes or clutch.

The clutch bite point was quite high, so I adjusted it yesterday but the smell was still there.

Last night I jacked the rear wheels up, ran the engine and put it into gear - there is a clunking noise that seems to be coming from the rear diff, definitely form the rear end. No similar smell when doing this - maybe it only happens when the wheels are under load?

Certainly no smell from the gearbox or engine was apparent.

A clunk from the diff certainly doesn't sound right, but could this also be the route of the smell? I would appreciate your help guys.

Are they easy to dismantle and service / repair yourself or should I take it to a local gearbox type specialist, or buy replacement form e bay?

It is a fireblade engine with a cosworth LSD (apparently - I bought the car, I didn't build it)

Rich