Seeing as how you've got a bit of time in hand, how about grabbing some packing polestyrene and using a hot knife cut it into blocks about 1/4 size of the camera.... then use it to tailor the blocks to fit around the camera then tape them on - obviously leave holes for anything you need to get at to change settings, or keep it on one setting. Gaffa tape over the top keeps it together and keeps quite a bit of water out - it shouldn't take too much work and ingenuity to make this so you can use 1 bit of tape as a hinge and the opposite to keep it shut. Sounds far fetched? Yeah, but it works. And you know, the Police aren't always bad guys - hell it's a difficult situation they're in there too. Have a word with one or two of them a few days before hand. Ok, they'll try to talk you out of it, but once they realise you're serious they might offer some real tips. Take care. (",)