Nick:

A 24 inch pot is plenty big enough for an M9 apple. I've had good luck with lots of things in 15 gal pots. That's about 15 inch by 18 inch on pot size.

Blueberries need a pH about 4.5 to 5.5 and work very well in pots as small as 5 gal.

Thanks for the reply, its all about space for me and I have to shuffle things, to fit :)

Both red and black currants are completely hardy so don't need to be put in the basement. They NEED to be outdoors.

The black currant should not have died back, only lost its leaves. If the buds are pointy they are leaf buds. If slightly fatter they are flower buds. If spherical you might have black currant gall mite. Check some images on line and pick off any spherical buds. But be certain first or you might be removing the flowers.

I would plant the red currant immediately in its proper pot rather than disturb it again later.

When you come to pruning them remember they are not the same species and need diffeent treatment.

Sorry yes, the leaves have gone, the stems remain how they were.

As to the buds they seem to be pointy, but if I should find round ones do I pinch/cut them off or prune the stem completely?
And yes I'm aware if the different pruning methods for each. Thanks :)