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Also under your Geospatial Agreement you will have access to Aerial Photography from Bluesky Mapshop which is free for every local authority.
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Using the OS Maps API in iShare
In order to use the OS Maps API as a Basemap in iShare you need to be on v6.0.0 of iShare which uses MapProxy (instead of Tilecache) as it supports WMTS.
Please see Proxying a WMTS Basemap for details.