If you've never held a race license before you'll need to do an ARDS test as part of the procedure to get your license, this involves a full day at a race school with a theorey test in the morning and driving round in the afternoon with an instructor with you. They dont examine you for driving fast just check your safe etc etc.
Total cost is something like £400-500 for the license and test, more details are on their website but its down at the minute.
What insurance is it for?