Pruning blackberries

I wouldn't bother. Just keep it well watered to swell them.
The smaller ones should swell and ripen later. They have a fairly long fruiting period.
Feeding with a sulphate of potash fertilizer in very early spring will help another year.

Thanks for that, I'll put a note in my garden diary for next year. My grandson says he'll make blackberry chutney with my glut!

Sulphate of potash fertiliser early Spring eh Sue ? I'll remember that too.

Works for all fruit Hank! it encourages flowering whereas Nitrogen based ones encourage green growth.