In the UK, it's rare for a civil airport ATC or RFFS to be able to access 121.5; usually ATC wise it's only the ATCC that has it by virtue of the 'Distress and Diversion' cell.
In the UK, it is now a requirement for ATC Control Towers and Approach Control Sectors, serving international aerodromes and international alternative aerodromes*, to be able to provide a service on 121.500.
As 121.500 is an ATC frequency, the equipment/recording needs to comply with the usual CAA requirements and as a result, a lot of units have signed an annual LoA with D&D to provide such a service on their behalf until such time they have the equipment to be able to provide the service themselves.
Whether these units will ever have the equipment to provide the service or will continue to sign a new LoA each year remains to be seen!
* A list of Aerodromes deemed to be 'International' available on request!