Fan/battery problems. Will not turn off.

I have been manually opening my bonnet and turning on the fan and then unplugging it again because if my fan is plugged in (they're obviously supposed to be plugged in) it stays turned on. I first realised this when I thought my battery was having problems as I would park my car and in a few hours go to drive her and the battery has died.

Firstly, what do I need to fix this problem? A new fan switch?

Also, now I must have the fan turned off for a few minutes before I stop so I give the battery a bit of charge because if I have the fan plugged in and park up, turn off the engine then turn off the fan.. or alternatively leave the fan cooling the engine only for a minute whilst I am at a petrol station.. she will not turn back on.

Any help will be brilliant, thank you.

Sounds like you need a new radiator fan switch - try GSF or Euro. Once this is replaced I'd give your battery a good charge and see how it goes from there.