So, I did
It cost me £570 including VAT, made a boo boo though I should have spent less and got last year's hardware, this is much better supported by Linux, I guess that's why apple do it, anyway, I installed Ubuntu server 16.4, boo boo number two, it has just been released and not supported by owncloud yet.
It took some doing but I have got all these unsupported bits of software and hardware to all work with each other, I actually enjoy doing this kind of thing, it would drive most people up the wall.
The cloud it's self is very very good, on the system I have put together I can have up to 150 users and have full control over how much space they have and what folders and functions they have access to, so I can give a customer let's say a photographer an account, I can give them some space, let's say 20 GB, they can then put folders and files in there, I will not have any access to them whatsoever, even if I physicaly went to the location on the local machine the data in encrypted I can't get at it, the customer has an option to 'share with' they put Inframe in that box, this could be one file or a folder or an entire folder tree, they can also leave a comment on it, own cloud then emails me to tell me said customer has shared something with me, I have the option of having shared files and folder auto syncing to me print server, you can guess the rest.
This is an absolutely fantastic system for us, so thankyou Alistair for promting me to look into this.