Land registered incorrectly

Good afternoon.
I have spent the last few days researching some land. This land was registered by the crown estate before they sold it in 2016. The crown purchased it from an insurance company in 1950 after they bought it from a family estate. They registered all the surrounded land. I've been trawling through the conveyancing documents from the family estate to the insurance company and then onto the crown. The land in question isn't included in the maps for the estate at any point. This was access land to other properties that they didn't own. Can you advise me the next stages as I was under the illusion that the land registry has a high threshold for regretting land. If this is the case then I would be interested on the documents used to register it. Many thanks

Good Morning Stephen - if you are interested in how land became registered then I would recommend firstly using our contact form to submit the specific details and your Qs. The support team can then check the paper/electronic records and advise on what details we hold and how to then apply for copies as appropriate. Public guidance: dealing with land and property - GOV.UK 
Titles can be registered based on deeds/documents as well as claims as to ownership