Used as a last resort - the back to basics process!!!!
1,Ring C/B to OFF. Then fully disconnect & isolate both ring cables from the consumer unit.
2,Go to where you think the middle of the ring is and disconnect that socket and split apart the cables so they don't touch.
3, Test which ring leg has the problem????
4, I then go live on that leg only to identfy the sockets that are fed - simple using a socket tester.
5, Isolate supply again.
6, Disconnect all sockets on this half of the leg. Remember to separate all the ring wires.
7, Meter out cables to see which pair of sockets has the short circuit.
8, The next bit is guesswork. You have to imagine where the cable is likely to run?? If it's easier to put in a new line then do it and cut out the original faulty line
9, Not the quickest of processes but if you know what you are doing, then it will find your problem.