New house, help with identifying?

Hi, we have recently bought and moved into a house with a fantastic garden.  There are several fruits we have discovered, and some I am struggling to identify. 

So far we have apples, pears, plums, elderberries, white walnut, raspberries, grapes (?!) and an enormous bush of what we think is a guelder rose, but a friend suggested it was redcurrant.  The berries, raw, taste revolting! Can anyone say for sure what they are from the attached photos?

I think the way the berries are clumped rather than hanging in chains says it is not a redcurrant but I am a total beginner and my teacher is google....

Thank you in advance, no doubt further identification questions will follow!