A hidden resource available at the Society of Genealogists (SoG), in London is SOGNET.
The entire SOGNET database contains 2,859 separate records. Within those records are many single level documents. A two page article written in the Genealogists' Magazine by Neville Taylor, (a long time volunteer at SoG) explains the research process.
This is my summary:
Search on the Society catalogue, choosing SOGNET as the location and type in a geographic place name as the Subject. For example, typing in Yorkshire retrieves 16 results of unique records. Then you will need to contact the SoG to ask about getting a copy of the record you need. If you are a member, you will receive a discount for research. Or make a visit to Charterhouse Buildings in London to do the search on the computers in the Lower Library.
This database is only available onsite at the SoG library. The agreement between SoG and the person who donated the collection was to ensure that the material be made available only in the library.
However, don't let that tiny roadblock prevent you from investigating the resources available. Considering the amount of indexing and transcribing taking place at the Society, this is good value for your money!
Another database which is available from your home computer, is SOGDataOnline, a database especially strong in Monumental Inscriptions from counties around the UK. Login to SOGDataOnline on the website with your account details.
For help with any of this material, please contact the Society of Genealogists:
020 7251 8799
Email enquiries via the Society's website: http://www.sog.org.uk/about/contact-the-society/
Taylor, Neville. "SOGNET - What is it and how do I use it?" p.28-29. Genealogists' Magazine, Journal of the Society of Genealogists. Vol. 32, No. 1, March 2016.