Looks like a Deutzia of some kind. they can take quite severe pruning after flowering. or if you are a little cautious remove 1/3 of the old wood this year. another the following and the final 1/3 the year after that.

when we moved in here there was one over 12ft tall. it got chopped down to 4 ft and was stunning for the next 10 yrs. it then died but it was at least 30 yrs old by then.

Thanks alot seaburngirl, ours is about 10ft and all in through the Hawthorn tree. Yet another trip to the tip after pruning lol.