I'd wait until autumn and give it a severe pruning then.

Mmm, that's what I thought Moongrowe, but it's so bad lots of it is laid on the ground.

Prune lightly now then and give a proper pruning in autumn.

Thanks.

Normally you prune red currants in autumn and black immediately after fruit is gathered as they fruit on last years wood, whereas the red fruit on old wood. So I wouldn't cut off any more than the minimum you need to until you know.
Black currants tend to have darker smoother branches and red ones have more greyish if that helps.

Thanks Steragram, I'll now take a closer look. That's a big help :)

Cheers Waddy - good luck.