Landmark Solutions (of the UK) are "a leading supplier of business-to-business services built on location-based data delivered from secure cloud platforms". Promap is their service to enable you to "instantly view, print, export and save Ordnance Survey Maps - ideal for planning applications, large or small." Included in their offering is
Historical Mapping:
- Individual Historic Map Plans and Packs (PDF), for printing
- Historical Map Packs for GIS (eg in PNG, GeoTIFF formats)
- Historical Building Plans (ditto)
They can also supply map "
data as a service", at a starting price of £250 per unit per year plus VAT.
This could be of interest to us.