As I see it, there are a few options for you now:
That does seem about it, good advice. I do find it hard to work out what to do without meters.

So easy when you can see exactly what is leaking, but even with all the tools,


these as well, when my front of house sockets tripped, I never did find out what it was which caused it. I had stopped the tripping by unplugging dishwasher, tested it, and no fault found, tested socket, and tripping at around 24 mA so that was about right, plugged it back in, and nothing has tripped since.
Could have been a spider or slug in a socket, or a faulty capacitor which has blown clear, I was lucky, my freezers run on an uninterruptible supply, so no panic.
Also, someone used a bit of sense when wiring my house, and split sockets side to side of the house, so by running an extension lead, I can without any trip hazard on the stairs, move items to be supplied from another RCBO, if the fault moves to the other RCBO I know I have found the culprit.