Hi Keith, I suspect a number of use here will eagerly watch them on eBay. It usually helps to mention where you are located as this is an international community. However, I'm guessing you are in the UK as I've just spotted an MBC listed on the UK site with the mention of a second one.
You might also want to add the word CP/M into the title as I gather they are CPM Machines. I think I would have put them on for longer. and also put a link to the following page:-
as there is more info there.