The Brooklands smells wrong to me. If you look at the written description in the ad it talks about £38K.Plus this add has been around a while now.I am sure something genuine at this price would have been snapped up in seconds.
Yes, the current Brooklands owner seems to be rather eccentric (to put it kindly)! Having said that, he may just have decided to get rid of it (at any cost) so I wouldn't discount it entirely if someone's interested and is prepared to deal with him. After all, it does have 'all the upgrades' including the latest version of the Brooklands exhausts which appear to be fit for purpose (unlike the original ones).