1925 was one of the dates when the majority of OS 6 inches to a mile maps were up-issued. I guess you are referring to that? - in the context of such a plan being used on a title deed plan or LR title plan to demonstrate proprietorship of a parcel of land? (I ask because 1925 was also the date of the Law of Property Act - a major reform point of land law in the UK.)
If so, then demonstration of adverse possession to LR changes the ownership.
Be aware that there can be a (small) difference between the legal ownership of land (as shown on a plan) and the physical representation of that legal boundary on the ground. If there is a fixed physical feature attached to the earth, like a wall or a ditch, it is not usually an issue, but unless the exact boundary has been determined, minor variations can exist
LR now use aerial mapping data to align physical features to their title plans and won't disclose their level of accuracy. It seems to me to be about +/-0.5m