OK, so, now you've stopped sniggering 
Intermittent THUNK / CLUNK (both technical terms, I believe..) from the rear end.
I think (guess) it is likely freehub related as the noise has been around for a while.
I've just stripped and lubricated the freehub (DT Swiss Onyx) which cured the squeaking and groaning (who'dve thought that rusty slime is not a good lubricant...)
Thunky / clunky noise happens when I pedal, mostly when I 'put the power down' having freewheeled.
Is it 'pawl / freehub body' related? - Pawls looked very slightly worn on what would be the bit that bites, body looked ok?
Cheers
C
