Everyone here should be able to tune a radio eg to 121.5 and put out a call whilst flying a (practice) forced landing pattern with a high rate of descent.
To what purpose? Sure, D&D might pick up the call from low level and call Full Sutton via the landline, so that they can get the word out on the radio, but I think by then the glider will have landed anyway.
Full Sutton Radio will not be listening on 121.5, and knowing the type of traffic that typically frequent non-towered airfields, neither will any of the traffic.