if they are all named as owners, they would all get a share. I think that the land registry only names people who have an interest in the house and not how much each share consists of ie they may not be equal shares or might be a life interest or whatever. I don't think you have enough information to know, first step is to get a copy of the deeds from Land Registry and see what it says. There is also the issue of whether they are named as tenants in common or joint tenants
http://www.findlaw.co.uk/law/property/buying_property/500189.html