@Andrewray,
Well, if you are referring to the Pimp My Pogo stick Institution, there is no better place than "Bouncing Dave's", just behind the Wishy Washy Splishy Sploshy Launderette in Catford High Road.
I once took my pogo in there for a revamp, and they did such a great job, I boinged myself silly right up until there was ice on the path and it became too dangerous.