Okay, so I was playing golf the other day and managed to lose my phone on the course. Rained for a bit, and the phone was found after it had stopped. Phone was off. Tried switching it on and it started up but then shut down.

Left my phone in rice for a few days, opened it up, found only a few drops of water on the back of the screen. Unplugged battery then plugged it back in.

Phone starts up fully, then restarts after a minute

Have flashed my phone.

Still does the same thing

Any ideas/suggestions as to what it could be?

First, make sure it's completely dry.
Second, check whether it has any rust-dirt-damage from electricity running while the water was inside the device.
Third, re-read Flashing N9.
Fourth, there is some mysterious N9/N950 Rescue CD.
Fifth, is it possible to ask for repair at a Nokia Service Centre if hardware is damaged? Water-damage is hardly covered by warranty, but still, they should have the best access to spare parts and repair tools.
Best wishes.