So now to drain the oil and get on with the job!
It was at this stage that I realised that the drain plug was where my 'blocking up' was. Incidentally, blocking up like this in the centre is not very stable - it relies on the weight of the wheel that is still attached not to fall over - but it cannot be blocked up anywhere else without putting weight on the trumpet that is being removed

OK a quick temporary re-jacking block moving and pick up hitch removal to get at the sump plug. B*****r to remove - ended up using an impact wrench - drained the vast amount of oil out - it's supposed to be something like 45 litres, I suppose I got of the order of 30 out - it had stopped leaking as the level had fallen to below the seal

That's all I got done today - tomorrow I need to remove the various linkages for brakes and the differential lock, and chock up the cab so I can unbolt the trumpet housing.
These trumpets not only have the oil seal, and half shaft bearings, they also have 'wet' ie oil immersed brake disks, a sun and planet reduction gear set, and a dif lock mechanism - but that's all fun for tomorrow!