So.... While searching the web for how to change the owner of a table on a Microsoft SQL Server I came across a lot of
sp_changeobjectowner '[olduser].[tablename]' , 'dbo'
(and unfortunately I see a lot of current suggestions on this - so y'all need to do your homework and if you are going to simply google an answer so you can get a "point" on MSDN you really need to make sure it's the right answer!)
I kept getting - Object 'olduser.tablename' does not exist or is not a valid object for this operation. - turns out that sp is deprecated in SQL 2012 and so won't work for us!
turns out what we need is
alter schema dbo transfer [olduser].[tablename]
All good! :)
Jamie