worth it at £50, some mid range vee pads like heatsink pads, and fresh brake cables will make the brakes massively better if you can pick up a trials freewheel second hand, not a shity acs claw or whatever is cheap on ebay, and the bike will be plenty reliable, brakes and freewheels are the driving force behind most trials, you can't really notive anything else being better when you learn, only a weight difference, even the nicest most expensive bike will feel odd and difficult when your learning at first, so go for it and have fun.