I expect you will have seen the " Sticky " on the PPRUNE Air Traffic Control section regarding the law in the UK regarding listening to these communications.
Regarding details of frequencies in use in your area I have attached a link to the NATS website and would refer you to the Aerodrome Index - Specific section where you should find details for your local airport. Also section ENR 3.1 has details of lower route frequencies and ENR3.2 upper route frequencies.
Also. if you Google " Books on Air Traffic Control " you may find some thing of interest.
Here is the link:-
NATS | AIS - Home