Chrysalis-owned Heart saw its London station grow its reach to 1.95m, up from 1.85m last quarter.
This compares with Capital 95.8FM's reach of 2.3m, down from 2.6m in the second quarter, and a share of 7%, down from 8.9% last time.
Capital hit the headlines last month when Chris Tarrant finally confirmed he is to leave the station's breakfast show, to be replaced by Johnny Vaughan.
It has also managed to secure Neil Fox for another two years, after speculation he would leave, having been passed over for the coveted breakfast slot.
The news was not all bad for Capital Radio Group in London, however, as the group's guitar and new-music station Xfm grew its reach to 502,000, up from 437,000 last time. Its share was 2.1%, up from 1.1%.
Including its national networks, Heart's total reach was 2.7m, down from 2.8m last period, although its share was up to 8.1% from 7.9% last time. Capital FM Network's total reach was 5m, flat on last period, while its share was down to 10.2% from 10.3%.
Virgin Radio also put in a strong performance in London. Its reach jumped to 997,000, up from 917,000 last time. Its share rose to 2.6% from 2.1%. Across the UK, Virgin had a reach of 2.9m, up from 2.8m last quarter. Its share was 1.7%, up from 1.6%.
Emap's urban and dance music station, Kiss FM saw its weekly reach in London fall to 1.5m, down from 1.6m in the second quarter. The share of the audience was 4.1%, down from 4.6%. Across the UK, Kiss's total reach was up to 2.7m from 2.6m last time, while its share was flat at 1.3%.
At the other end of the musical spectrum, GWR's Classic FM saw its reach drop to 6.5m from 6.6m, and its share of 4.5% was flat on last period.
Jazz FM, owned by Guardian Media Group, continued to grow with a reach of 1.5m, up from 1.4m last time. Its national share was 0.7%, flat on last period.
BBC Radio 1 continued to hold steady as its national reach was 9.8m, flat on last period when it dropped below the 10m figure, and its share rose to 8%, up from 7.6%.
Earlier this month, Radio 1 moved to stem the loss of listeners from its breakfast show as it dumped Sara Cox in place of drivetime presenter Chris Moyles. Cox will now front the drivetime show in place of Moyles. Cox was moved after she lost 473,000 listeners during the second quarter of the year, almost half of them from London.
If you have an opinion on this or any other issue raised on Brand Republic, join the debate in the Forum here.