Question Author
juliefer and Mancunian - I agree, it's really confusing especially if you regard land holdings as property (they look after or own lots of coastline and a large part of the lake district for example). As you say, its time for an educated guess and as I just want to finish it I think I'll put 444, the total of bridgenut's answer. I think National Trust for Scotland is a separate organisation.
Just got 2 to do now and I then I can .... move on to another quiz! I must be obsessed lol