I have managed to ruin the thread of my hotend when changing nozzles. Now loading material just pushes the nozzle out of the heater block. Does anyone have advice how to temporarily fix this as I need to do a print urgently (for a funeral on the 2nd) and it seems impossible to source a replacement in the London area at this time of year. It’s my own fault for not having a spare.

You can try setting the nozzle in the hot end with high temp epoxy.