Personally think these may need to be sold off much cheaper than the some of parts. I can't totally speak for the UK market, but it's accepted it's not moving much. There are some choice, desirable and some expensive parts on some of these bikes, but I do need to say each bike is a bit of a mish-mash overall in my eyes. Hope I haven't offended.
Pretty sure any buyer would split for parts they need, or rebuild according to their tastes, or just for the frame because it's their size. List individually with a reserve at £250 each or the entire lot for something like £2500 and see how it goes would be my advice.