Right I've had a bit of a search on this, but couldn't really find a definitive answer to what would be causing it.

Went to open my car tonight, and the front passenger door refused to unlock for about 5 minutes. Obviously I couldn't open it from the inside as it's deadlocked.

After several locks and unlocks it eventually opened as normal.

Any ideas on what to check before I find the door is completely stuck closed?

A pillar wiring plug and socket, lock motor and wiring/plugs. If the motor doesn't cycle, lock itself could be stuck.

My doors kept one min bein fine and the other min would either not lock, not open or would keep open and closing. All it was was the fuse had come loose somehow, just tool it out wiped it, put it back in and everything was fine

I'd get this sorted pronto. It's a right mare to fix if it deadlocks shut possibly involving a chisel.