Nigel, i feel you brother. I just sold a 2004 BMW R11S Boxer Cup Replika with under 4k miles on it. It looked like just out of the wrapper, had abut 3500 miles when I bought back in May. Every mile I put on the bike, every pothole that couldn't be avoided, every little pebble that would come in contact with fairing would make me cringe. This was a limited production bike in the US, only 300 copies sold in 2004. My choices were ride it sparingly, put it under covers in the garage, drag into living room or sell it. I chose to sell it. It did fetch top price as the rest of the R11S and R12S market in the US is depressed. I didn't need to sell it, but not riding the bike I would be causing it harm. Hoses, fluids, pumps,bushing etc. would start to deteriorate and after a while the bike would need reconditioning. The new owner has different take on things and wants to ride it just shy of 10k at which point he will make a decision to put up on display or...
My motorcycle history contains other examples of low mile, pristine bikes that I loved to own but stressed to ride. When buying my 1991 Bimota YB10, seller gave me a choice of two bikes - a spotless, show queen or one in daily rider condition. I went for the daily rider and could not have been happier. I ride it with a bit of care, but I do ride it. Mileage is a consideration only when it comes to maintenance intervals. The Brutale I have was extremely well cared for by the PO and now my self. It had over 8k miles when I got it and I put about 2k in about 6 months. I have no qualms of riding it, modifying it and enjoying it. If it had 800 miles on it I don't think I would enjoy it in the same sense.
The YB10 is the bike that I plan to have for as long as I can ride and even past that. Brutale hopefully will be around for a long time considering the coin I am planning to drop on it in terms of mods. To sum it up, buy clean well maintained machines and enjoy them. If the mood strikes and you want to sell them, go ahead. If you want to stick them in the living room you can do that too. They are bikes bought with your own hard earned cash and whichever choice it will be go with the one that makes you happy.