I'm probably too late for you replying here, as I guessing you are going this morning? I used to go there regularly, but like most places, since lockdown everyone and their dog now goes there. The 1st hide (steel one, so the tw@'s can't burn it down) is probably your best bet with 400mm as the perches there are relatively close, the 2nd hide has more scope, but the perches are too far away from the hide, however you'll get a better chance of seeing one of the foxes there. Walking the canal will give you more chances of seeing/photographing kingfisher's, so my advice would be , be prepared to be mobile, don't neglect the feeder stream that runs adjacent to the footpath, there's usually plenty to photograph along there. It get's quite busy in the hides, especially as it's bank holiday monday, so you may need to be prepared to wait for a seat to become available. Good luck.