Hi, Like ElDopesta says, If you experiencing a big loss in power this could be because your leaking pressure from the hoses. Having said that, if they are 'popping off' it seems they are not so much leaking as just stretching, then bursting.... This would cause a power loss but not a huge amount. I suspect something else might be going on in there...
Again like ElDopesta says, worth getting a full service with oil change as a minimum. Ask them to look at your turbo seals if oily inside hoses, check dump valve for sticking or leaks. As with all high performance cars, they are tuned so much that they are liable to little things occasionally going wrong. If you've only just got it, you never really know the history or what previous owners have 'tuned/played with'
Im in North London so i have no ideas about specialist garages near you, but im sure you can find one.
Good luck and hope its nothing serious. Steve