IT'S ALL WORKING AGAIN!
As soon as the weather warned up a bit today, and the condensation after the sudden hail/snow disappeared of the battery connections, the window works again, along with the driver and remote lock! Yay!
There's still a bit of water on the bottom of the tray, I've left the hidden cover up, so it can dry better, but it all seems working great again!
I'm not sure that's what caused the issues at once, rather strange to be fair, temperature suddenly drops 10c and electrical parts go offline. To be safe, as recommended I'll check the b pillar connections later, to make sure all good and rust free as much as possible.
For now I'm just glad it didn't cost me anything as I've already forked out quite a bit this year and insurance here soon as well.
Thanks for the help folks!