The next EXR event is in Portsmouth on the 19th-20th May. If that is too far, EXR Guildford is on the 9th and 10th of June. I should stress that Extreme Robots have a limit of HW spinners tip speed, which is 125mph from memory so you'd need to be able to limit the speed (and not by just throttling the ESC either). Robots Live, as noted, don't allow spinners - I'd personally remove the drum and fit something else in its place for those events because even without a spinner, a live event is still easily the best (read: safest) way to get some experience in.