We are a GSD club who train and compete in IPO/IGP trails. Membership is currently FULL....
There's a list of IPO clubs on the GSDL Working Dog website What is IPO and what is the difference between Working Trials and IPO?

Working trials originated as a competition for service dogs to compete against each other.
This was formed about 40 to 50 years ago by a group of civilian dog enthusiasts as a means of being able to train dogs to a high standard and compete against Police and service dogs. IPO is like working trials it involves 3 phrases; obedience, tracking and protection. The purpose of IPO training is to assess and mould the dog’s natural abilities to track, protect, and teach the dog control through obedience. It has been considered by some to be a test for breeding in that during the training the degree to which the dog possesses these working abilities becomes apparent.
To be eligible to do both Trials and IPO, it is essential that the dogs have a sound temperament. It cannot be shy, sharp, vicious, or have poor nerves. A responsible trainer would never train a dog with a poor temperament in any form of man work for working trials or IPO. It is also important that the trainer knows when to back down and when to admit ignorance in order to keep from ruining a dog. Good socialisation during puppy-hood is critical. Poorly socialised dogs will almost certainly have problems getting started and will require more groundwork.
IPO sport compared to trials is still very young in the UK. In other countries throughout Europe you can find a local IPO dog club in almost every town. The temperament and working quality of the German shepherd’s now being imported to the UK has started to benefit all involved in working the breed.