Their site is very slick and their covers seem polished and attractive. Two worries:
1) Their address is 71-75 Covent Garden, which sounds like they've taken over three buildings in one of the most expensive areas of London--but is in fact rented office space from a firm that advertises use of their "prestigious address". Don't get me wrong, it's physical office space with a lot of lovely amenities, so it's not one of those virtual address scams, but it's not as impressive as it seems at first.
2) This is the big one: the person editing the Luminosity website has no idea how to use commas whatsoever. It's still a small business--do you want to take the chance that your book will have errors added, rather than removed?
