Answering my own question here, but the ABCs (combined print and digital) for women's magazines in 2021 (as per Press Gazette) showed that UK Cosmo was outselling those other Hearst titles, yet also suffered the biggest drop in sales from before:
Average per issue - UK/ROI total - % up/down in sales - % actively purchased
Cosmopolitan - 138,243 / 123,615 / −26% / 85%
Red - 116,243 / 106,284 / −16% / 87%
Elle - 109,568 / 99,480 / +3% / 36%
Harper's Bazaar - 105,047 / 87,010 / +3% / 35%
The ABCs for 2022 won't be long in coming out.
UK Vogue sells more in general (190,192 and down only 1%) while UK Tatler and Vanity Fair have much smaller circulations, but they target a more niche (and monied) market, so you can have that smaller audience but a more effective reach with your content/advertising. I would imagine UK Bazaar benefits from a bit of that as well.