The Specified Area is a blanket area that covers key areas within London but it is not applicable to UAS Operations
The Specified Area (R160) is a blanket area that covers an area within London and is only applicable to single-engine helicopters only.
With may find when looking at the apps such as Drone Safety Map and Altitude Angel that the area also contains R157 (Hyde Park), R158 (City of London) and R159 (Isle of Dogs) which are restricted areas and you will need to apply for a Non-Standard Flight (NSF) Application from NATS.
This is the same process required to get permission to fly within the Flight Restriction Zone of many of the major airports.
You can fly your drone within the Specified Area, however, you cannot fly any drone within R157 (Hyde Park), R158 (City of London) and R159 (Isle of Dogs) without express permission from NATS. This includes all Unmanned Aircraft including the DJI Mavic Mini and the DJI Mini 2.