I believe the couplers are standard dellner ones, so assuming they have a vehicle with them at the right height shunting should not be an issue. As the 360s, 379s and 345s maintained at Ilford also have this design of coupler having a mechanically compatible vehicle shouldn't be too difficult assuming it is of the right height - the standard coupler centre height for UK EMUs is apparently 925 mm above rail level, but I've been unable to find whether this applies to DLR stock.
The essential things in life are seen not with the eyes, but with the heart. --Antoine de St. Exupery
If only I was looking at this forum in January......
I know a DLR controller and I can confirm their wheel lathe has been out of action for months. This has indeed led directly to the shortened trains mentioned in this thread.
Ilford's lathe is apparently the only one in the London area that can accomodate DLR's profile but of course it has plenty of its own work to be getting on with, so the DLR's needs outstrip availability.