Before you spend £300+ on remapping your car, to gain about 5bhp, I would look into other ways of improving your car. Also remap's are really only helpful if you have already improved air intake and exhaust.
What have you done to your car so far?
Are the brakes and suspension both standard? Uprated disc's and pads would be the first thing to do, then the suspension, lowered springs, or coilovers if you want to spend the money. They need to be set up properly though, and not just slammed. This will improve cornering and give you more confidence in braking.
Have you thought about weight reduction? The cheapest way to improve your power to weight ratio! Stripping the rear seats and isofix bar out, will help. It depends whether you use them or not. You can go further by removing sound deadening, belts and trim.