Yellow inflorescence

Taken with/in a flash! This is a welcome splash of colour in the front garden. I don't know what it is called but those who have mowed the lawn beneath it have called it a number of names I won't repeat as it has lethal thorns! My daughter didn't want it many years ago when they moved into their new house and I inherited it. It was about a foot tall! Now it's nearly up to the first floor and is regularly trimmed.

I think it may be a Mahonia. I've just been looking at a garden book!