Wow. I should have passed it to detective Sean earlier! I never thought for a minute to ask on here; I thought the chances of it belonging to one of the SOTA fraternity would be very slim.
It was Jimmy that found it, so I will have to double-check with him when it was he found it, and on what summit (think it was SP-004, but not 100%). My memory is hazy, but his will be clear (as ever).
It has sat dormant since the discovery, as it was locked and I had no way of geting into it to find any numbers, clues etc. I had forgotten all about it until rediscovering it in a kitchen drawer a few days ago, then Sean was round, who is a mobile 'phone engineer (or something, don’t know the exact job description).
I’m astonished that his investigations have linked it back to SOTA, and intrigued to know more. Plus, I feel a bit bad that I never mentioned it on here!