Glad it turned out in the end

Future references, chances are the cake rose in the middle because the cake tin was too small for the amount of cake mix.

Some tips for a flat cake -

Fill up a cake tin to half, and no higher.
Place cake in the middle of the oven.
Place a damp/wet towel around the outside of the tin and pin it into place before going into the oven.
If there is a hump, place a clean tea towel or simular onto the cake and carefully press down.You must do this as soon as it comes out of the oven and prob wont work for huge humps.
Stop opening your oven to look at it!
Dont get too temp happy, nice and slow does it