The front diff on my Disco 1 has an excessive amount of play on it...I checked it when it was up on the ramps.... when I come to a stop with foot on the clutch there's a fair amount of "knocking" noise coming from the front end... can I replace the innards of the diff or do I have to replace the whole unit?

check for wear in drive flanges with plastic caps of and rocking truck on clutch need two people ,your more likely be able to change pinion bearings if this is causing slack ,if worn in diff gears and shaft they can be replaced with a kit ,but mark position of crown wheel so goes back in exact same position on carrier , check holes where shaft goes through for wear too

Thanks James....I'll try and check that out tomorrow....regards