They would only have given notice to interested parties such as the registered proprietor, mortgage lender etc... based on any existing register or deeds they had.
Have you checked your title deeds to see if any right already exists?
You could try getting a right of way or similar registered by say implication (previous use) or prescription (accrued right over a period of 20 years).
I'd suggest ringing the Land Registry who can be very helpful with these matters and suggest what you can do, forms needed etc...
You can find the relevant office here...
http://www1.landregistry.gov.uk/regional/
Alternatively you could sound someone at if any local law firms run free legal surgeries or a free initial consultation though advice may well be limited.
If you are querying the possessory title, please note that the rules have changed recently so it will have been done on the old rules if that long ago.
Exlcusivity, however, would relate to your neighbour holding the land to the exclusion of the true owner, renters, hunters, and anyone else who entered the land with the permission of the true owner.