Alton towers Is the worst for SRQ.
When I was queing up for Rita, I thought 'Yes!!, A single rider line' (I used these extensively ot ROTM back In October) So I got In line and waited for about 15 minutes before anyone from the SRQ got on, So then It started to rain (Rita has an outside queue, with no roof) And the ride broke down 2 times because of It, So after about 1 and a half hours!! of waiting In the SRQ I FINALLY get on (Great coaster by the way) and by the time I got of, We had run out of time and couldnt ride Oblivion.
So In my experience American parks are MUCH better and organized than English parks.