JB wrote:
I have a whitecurrant bush at the back of my garden, or at least every
year that I've watched it so far it has produced whitecurrants.
However this year everything on it is ripening now and turning into
redcurrants!

Is this normal? Has it just never ripened properly in the past? Do
they 'revert to type' after a while?

My immediate thought is that you have pruned rather hard, and removed
the grafted variety in favour of the root stock.

Mark you, I have no idea if whitecurrants are sold grafted onto a root
stock, so you are free to ignore me if you choose.