Spectrum Radio Network have advertised availability on the 1548 MW/AM frequency which covers North London. This frequency is currently occupied by Love Sport, and it is not yet clear what will happen to that station.
Spectrum also have a London wide DAB slot, and two London DAB+ slots available. For those and the MW frequency, Spectrum are offering part time slots, to allow for smaller stations to come on-air for a reduced cost.
For full details visit their website at spectrumradio.net/airtime/.