I confirm that Ordnance Survey does hold some of the information you have requested. Where the information is not held this is stated. Taking each request in turn, I confirm the following:
OS publishes third-party information from authoritative bodies, the measurements given at question 1, 5, 6 and 7 below represent the geographic area covered by this data. We received the data in categories 1, 5, 6, and 7 from Natural England.
1. England Coast Path Coastal Margin
We hold data representing Coastal Access land, this represents the Coastal Margin and is 804.5 km2.
2. Village Greens
3. Doorstep Greens
4. Millennium Greens
With regard to categories 2,3 and4 above, we do not hold the requested information.
This information is not captured or classified in our data; we are therefore, unable to provide you with the requested information.
5. Registered Common Land
6. Countryside and Rights of Way Act, Section 15 Land
7. Countryside and Rights of Way Act, Access Land
With regard to categories 5,6 and 7 above, we do not hold this data in these separate categories, they are instead held in a single classification.
Under the duty to provide information and assistance in accordance with section 16 of FOIA, we can provide you with the total combined figure for categories 5, 6 and 7 which is 10149.1 km2.
You may wish to contact Natural England as they may be able to provide the figures for each individual category listed at 5,6 and 7.
8. OS Open Greenspace
Please see the attached .csv file which provides for each function within OS Open Greenspace the total number of m2, ha and km2 (the latter two values shown to two decimal places) associated with each function.
Please note that OS Open Greenspace data is not supplied with an area value calculated from its geometry, this would have to be calculated separately; and the polygons are ‘generalised’, they do not follow exactly the underlying topology and the calculated areas provided are therefore approximations to real world feature objects.
9. Can I also have a precise definition of what is included within OS Open Greenspace as it may overlap with other categories
Please refer to our website page for OS Open Greenspace, in particular the OS Open Greenspace support documentation (PDF) provides a definition of OS Open Greenspace as ‘publicly accessible greenspace’ which are sites that the public can use for recreational activities and outdoor leisure. It also lists the various functions (the purpose of the greenspace site).