It is probably caterpillars eating the leaves. Assuming you had a lot of flowers on the bushes it was probably lack of pollinators at that time.

thank you, so how do I get rid of the Caterpillars can you advise and when do i treat the bushes,first year gardener.

You can either pick the little blighters off by hand (wear rubber gloves if you are squeamish) or spray with a solution of vegetable soap, don't use washing up liquid unless yours is environmentally friendly washing up liquid. It is too late for this year now so I would just let nature take its course.

The other thing you could do next year is spray with something like Garlic Barrier this is a systemic that deters the moth/butterfly from laying their eggs on the plant. Seemingly they, and flea beetles and aphids do not like the smell of garlic and whilst this will not taint your crop or actually harm the insects and butterflies/moths it will deter them. You need to make sure you spray the underside of each leaf as well as the topside though!

Oh and welcome to GoY Ibrox

The caterpillars responsible are those of the gooseberry saw fly which produces three batches of brood between June and September. The simplest method of control is to keep an eye on the bushes and remove the tiny caterpillars as soon as they appear. With practice you can spot the eggs which are often in a sort of woolly/silky sack.
This article might be useful..
http://www.dgsgardening.btinternet.co.uk/goosesawfly.htm