Ah. There appear to be over 850 grade I buildings that do not have a NH number:

On Fri, Jun 5, 2015 at 7:19 PM Mike Cummins <b13@b13.co.uk> wrote:
Andy Mabbett wrote:

> Mike Can you post some examples, please? What do you mean by "in the
> text" - the Wikidata descriptions? Wikipedia content?

If you look at the Baddesley Clinton entry on Wikipaedia, (http://en.wikipedia.org/wiki/Baddesley_Clinton) you will see that in the right hand box, Owner: National Trust. If you look at the Wikkidata entry (https://www.wikidata.org/wiki/Q4386885) that information  is not present.

Conversely, look at Packwood House (http://en.wikipedia.org/wiki/Packwood_House) and see that corresponding Wikidata page has a statement of 'Owned by the National Trust'. (https://www.wikidata.org/wiki/Q7123054).

There are many, many examples.

I have escalated my emails to both Historic England and the National Trust to get their data in a useable form. Apropos of which, the WayBackWhen site is particularly interesting :-) 

> All: thanks for making my good friend Mike welcome.

Thanks all. My first paid computing job was to write a database system (1984) and I have been involved ever since. been a while since I played with really big data (most I have played with recently has been the Postcodes issue) but am looking forward to making even a slight improvement for Wiki.

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