Ha! Thank you - can I ask how you searched that? I tried a few combinations but never got past USPS. Unless you just went straight to the RM website and tried there?
I didn't. Looks enough like a postal service tracking number that I've seen enough of that I guessed it was RM and tried their website. Next step would have been to try the Deutsche Post website but that is probably encrypted*.
Looks like a postal service (UPU?) tracking number originating in Germany.
Royal Mail says it is in Plymouth North and due for delivery on the 30th. If you haven't got it I'd say it is lost.