[bluelou]

What is a good feed for redcurrant brushes? And any good ideas for keeping the birds off?

[Trillium]

I rarely feed mine, they're so hardy, but if you feel you need to, then throw some rotted manure around the base but not touching the stems.

Only foolproof device against birds is netting which you'd need to tie snuggly at the base as some of the brazen thieves would hop into the tree from below.

[hightide]

It might be a bit late to feed them as the leaves are open and the flower stalks are forming on mine. I usually give them a handful of Growmore and a small amount of Sulphate of Potash each February and apply a mulch afterwards to retain the moisture. If you have light soil up there Bluelou then you need rotted manure, compost or peat around the bush as Trillium says.
     
I use debris netting, but only after the fruit starts to form, to protect the berries from the birds. Mine are all single cordons so it is just a question of throwing it over the stakes and pegging down. I did make a proper fruit cage when I first started, but some kids got on site and trashed it. 
     

[bluelou]

Thanks for that. I have got the other half to make a frame this weekend, so i can put netting on it when the berries start to show.

So do you not feed through the summer months?

[Trillium]

I don't. They need only one feeding per season. I prefer to do any feeding in the fall so they're ready for spring cropping. Often I don't even bother and I'm still overloaded with berries.
Considering I'm on heavy clay soil, that's not bad.