How do you release jelly (jello?)

Trying to make a ginger (orange flavour) cat jelly.

I was given a cat shaped jelly mould a few years ago but never used it. Then yesterday I decided to make an orange jelly for fun. I could have added fruit or trifle sponges to strengthen it but I wanted it to be pure jelly, and I was going to call it ginger and maybe take a few photos in different places before we have it for tea.

I tried mixing the jelly powder but I didn’t realise it hadn’t all dissolved until I cleaned the bowl I’d made it in, would that weaken the jelly? Then I couldn’t lie it down level because it’s head is higher so I had to prop it up in a bowl to put in the fridge. I let it set overnight. But how to get it loose? I tried running a thin knife round the edge, then turned it up on a plate, wobble, no! Tried running the mould under the hot tap, no! Tried tapping the mould, whoosh, a few bits dropped out, tried a knife again and tapping.. It finally came out, a saggy, wibbly wobbly brother cat to the solid mould.

Does anyone know what I should have done?