Okay, I believe I have fixed the problem, at least so far, touch wood! In case anyone else is having this problem maybe this will help.
I noticed the problem began occuring when playing other games and became more frequent, I put this down to the fact DAI forced me to upgrade my graphics driver and previously I had never updated it because, well, if it ain't broke don't fix it! After spending a lot of time testing different drivers I finally found one that appears stable. For me it was Nvidia 344.75. I tried many later drivers than this and each time the problem kept occurring. My graphics card is Nvidia GTX 660, I guess if people are having this problem and their system meets the minimum requirements to run the game then try using different drivers and hope you find one that works.
I assume most people will already know this and it is probably quite basic but maybe this will help someone.