As well as a fuse in the main fusebox, there is probably one hiding in the rear of the radio itself. Unfortuately you will require the two special extraction pin thingys (if it`s the same as my 2000 model) which Halfords sell. Mine drove me up the wall until I accidentally spotted this 2nd fuse.
Thanks everyone, I tried swapping the fuse for another and it came up saying SAFE, then I put the old fuse back in and it said SAFE so I looked in my book thingy and it told me to re enter the code so I did that...and it's working now