Mk1 850 seat

With the exception of the hinged Mk3 850 seat, any Commando Roadster seat will fit any frame. 

The main difference from year to year, apart from the change from fibreglass to steel bases was the cover. The Mk1 850 shared a sort of quilted airtex cover with the last of the 750s and the Mk2s had a trendier,  more Japanese quilted style. I quite like the earlier type to ride on, but it's personal choice. The most important thing is the quality of the foam. Andover seem to have got that right...Cheap sponge foam is a nightmare as the base is not far below at the front....I'm not sure that I'd buy anything as critical to ride enjoyment as a saddle via eBay.

I fitted Craven panniers to my Mk3 to go the first International Czech Rally. When would that have been ? Early nineties ? With the panniers fitted, the hinged seat didn't work and a 2000 mile round trip without being able to check the oil level didn't seem like a good idea so I quickly bought a pattern Mk 2 saddle...It was purgatory. I did long days, with the first stint through Germany requiring seven fill-ups on the Roadster.  I threw the saddle away when I got back.