Gordo,
Check this link out for an Enduro version for sale on EBay some time ago. One of the photos shows the numbering sequence on the headstock and might help to identify your bike.
https://www.ebay.co.uk/itm/1972-Rickman-Zundapp-125-ISDT-Enduro-/132355792244?ul_noapp=true&ul_ref=https%3A%2F%2Frover.ebay.com%2Frover%2F0%2F0%2F0%3Fmpre%3Dhttps%253A%252F%252Fwww.ebay.co.uk%252Fulk%252Fitm%252F132355792244%26rvr_id%3D0&nma=true&si=gIkLm5kr%2BthAkYHpV7kmIVx7Ifo%3D&orig_cvip=true&nordt=true&rt=nc&_trksid=p2047675.l2557
If any Seeley Honda TL 200E owners need a manual, send me a PM with your e mail address and I'll send you a copy.
Happy to share in the spirit of trials ?
I think if it has the upswept pipe it will have originated as the enduro version.
Mine didn't smoke this much
Sorry I can't help you with dating/identifying the bike from the frame number, but maybe somebody else can help
The Rickman Enduro ISDE version was mine - a great little bike.
If yours is the MX version I guess it will be one of these :
https://motocrossactionmag.com/classic-motocross-iron-1971-rickman-zundapp-125-metisse/
Found these photo's in my photo reference collection, but can't recall any details about them.
Plus a photo of my ex Army ISDT Rickman Zundapp Enduro - a little belter it was
Being quite tall, I always thought the handlebars on my Majesty were too far back. so I cut the bar clamps off the top yoke and machined and welded them back on inline with the fork legs, and it steered a lot better