Does anyone kow a good place to pick blackberries in bristol?

We used to pick them around the woods at the bottom of Wellington Hill West/Southmead Road which isn't too far from Blaize Castle. I think that all the farmland hedges at the back of Horfield Common, end of Kellaway Avenue, has now been built upon but that was another good source, Blaize Castle could well have briars in the woods.