Hi there Geoff,
Yes, indeed here spring has, theoretically, arrived. However temps are still on winter ranges. But that doesn´t seem to bother or worry my Acer Palmatum, which in turn has already begun sprouting all over the place (see attached image). Also, I did a repotting on him two weeks ago. Since the tree was healthy enough I trimmed 50-60 percent of the rootball, so it could fit the new and smaller pot I had reserved for him. So far, so good.
I do believe your time for doing your repotting duties on your deciduous it´s closing its window. Hurry up, make up your mind and do it at once, provided your trees are healthy, that is.
Hope this might help.
Alain