gearbox/clutch noise

Evening Folks, went out for a run today and after 25mins ended up in heavy traffic so lots of timee on the clutch. after 5-6 mins a whurring/gratting vibration thing happened when trying to pull away in first a lot less into second. I went to turn around and had the same type of thing releasing the clutch in reverse. Pulled into a garden centre to eat and think ( I find they work well together. ) Called recovery, first chap arrived in a transit to do first fix diagnostics. Said it was gearbox not clutch.
Recovery truck then arrives 30mins later. Recovered and this drivers diagnostics, not the gearbox!
Back out in Disco 1 300TDI on driveway and symptoms as such,

At idle no noise
Clutch in no noise
Forwards release clutch, a whurring come gratting noise with a vibration through the clutch pedal. However less than when I had initial problem
When reverse selected next to no problem.
As I drove backwards and forwards 6 times I only had the symptoms show once badly and once slightly
I hope this gives You true mech heads enough info for some gratefully appreciated diagnostics.
Thank You Chrisarb

hi do you have any oil round the bellhousing if so your clutch could me contaminated.

or other contamination ie, water, mud ect.

Ok I have had serious coolant issues lately. stripped everything out to waterpump housing then had to do it again because the second hand housing I bought allready had a waterpump on it. The pump leaked so I stripped and rebuilt all again. Now I need a new radiator.
That said could my water loss have some how found its way into the clutch.
If so do I have to drob the gearbox etc to decontaminate the clutch?

i dont think that would reach the clutch have you gone in any deep water of off roading.
also are you using oil.