Despite what mineral prospectors may tell you, the ownership of the mineral rights to your land (or anyone else's) does not give them the legal rights of access to carry out testing or exploration without your permission.
Possession of documentation indicating mineral rights ownership is not in any way a right of access and you are legally able to refuse.
The only way a prospector or mining company can force access to land is by the 1966 Mines Act, which requires referral to the High Court via the Secretary of State. This would create a huge amount of work and investment and would be very negative for community relations. At exploration stage this becomes an unlikely route for these companies.