I guess I'm missing something here. Are you saying that in the UK, once someone is lined up with the runway, you can't turn base in front of them?
It happens all the time here. At Livermore there's often someone on a long straight in and they'll turn pattern traffic in front of them as long as they're far enough away.
Reminds me of when I flew out of Biarritz a few months ago and they held us for takeoff for a plane that wasn't even visible, which meant several minutes holding instead of just taking off in front of them. If they tried that at Palo Alto, throughput would drop to a tenth.
n5296s