TD5 loss drive

My partner was driving to work this morning and suddenly heard a Big Bang and lost all drive, I went to rescue her, and tried putting in both low and high box and also diff lock, it moved about a foot in diff lock and made another loud bang and lost drive again, however diff lock has always been dodgy, and popped out. So I decided to tow the Land Rover back home, where it was making a very loud whining and grinding noise, would this suggest the transfer box or a drive shaft, because when I but it into gear now and let the clutch out, all there is, is a grinding noise and no movement.

any props spinning when its running in gear
put a 13mm spanner on diff lock spigot and turn as fa clockwise as it will go
does changing gear alter the speed of the grinding

Sounds like blown CV