Dylan would probably have got a shock if he tried to play with it grindle! We have a black & white cat who visits during the night & tucks into the bird/hedgehog food & a few times we've caught it on camera with the hedgehog eating beside it, both seeming quite tolerant & unfazed. This was a couple of nights ago - one on each tray.
There are a lot here too grindle, we've seen about 5 different ones on the infrared camera at night but the big black & white tom seems to have scared most of them off except the tiger tabby & the hedgehog must be pretty tough to stare it down over the food!
Unfortunately today when I went down to the 'Wildlife' pond there was a dead hedgehog in it. Fished it out and gave it a burial. Poor wee thing must have been unable to get out even though there are shallow edges specifically to allow anything falling in a way out.
That's really sad sweetpea, I always worry about that happening but our pond has little steps formed in it at one end & there are lots of pots of plants in it which I think they'd be able to clamber up.
You could try leaving a small plank/tree branch in the pond as well that anything could climb out up, I try to remember to leave a stick/twig etc. in buckets & watering cans which I leave outside as I once found a frog struggling to get out of a metal watering can which was part filled with rainwater, it had climbed in but was unable to get a grip on the sides to jump out.