Since the issuing of EASA aircrew licenses a FRTOL is not required.
However; in most States the issue of a FRTOL is still required by the International Telecommunications Union (ITU) it is covered under Art 37 of the General Radio Regfulations which states:
37.30 2) For aircraft radiotelephone stations and aircraft earth stations operating on
frequencies allocated exclusively to the aeronautical mobile service or the aeronautical mobilesatellite
service, each administration may itself fix the conditions for obtaining a radiotelephone
operator’s restricted certificate, provided that the operation of the transmitter requires only the use
of simple external switching devices. The administration shall ensure that the operator has an
adequate knowledge of radiotelephone operation and procedure particularly as far as distress,
urgency and safety are concerned. This in no way contravenes the provisions of No. 37.2.
37.4 4) Nevertheless, in the service of aircraft stations and aircraft earth stations
operating radiotelephony solely on frequencies above 30 MHz, each government shall decide for
itself whether a certificate is necessary and, if so, shall define the conditions for obtaining it.
The UK still requires a FRTOL and the privileges are endorsed in Section XII of both EASA and National Licences.
With regard to the original question, there is no reference to a renewal charge in ORS5 however they will charge the same fee as for initial issue except where the holder has another flight crew licence when no additional charge is made for a FRTOL.
SRG1106 states:
If no Flight Crew Licence is held a separate FRTOL is issued.
If a UK issued Flight Crew Licence is held the FRTOL will be entered on the licence, which must be submitted with this
application.
So if you have a lifetime National or EASA licence the FRTOL privileges are imbeded in it.
Schedule 8 gives no indication of any expiry date for a FRTOL so it must be issued for the lifetime of the holder.