Are you still after one HelmetHair? I have a 2001 (51) 125 Williams, 2 previous owners. Purchased privately from Mark at Guildford Vines BMW in 2014, who also did some private servicing on it (and Vines did the other service work when Mark was out of action).
Has been SORN (dry garage) for about 2.5 years. New belt at 28k. I'd guess it ended up at about 30k but need to get to it to confirm.
Bodywork is very good - I had office parking when it was in use. Have had MP3 since. Sorry.
It did start when it went into storage, but didn't last time I tried maybe six months ago. Eletcrics came on, but nothing happened. I'm no mechanic.
If interested I'll clean the layer of dust off today/tomorrow and get photos. Otherwise I'll get around to advertising it in the next week or two.