I know this is an old thread but just thought I'd say that in Sheffield I rely on AW, Viva and UKAdultzone. UKA brings much less than the other two, but enough for me to buy Premium, and I get much less TW from it. If you email Sharon, the owner, she sometimes runs special offers on Premium.
I get far, far more TW through Viva and it's absolute hell for bareback seekers. I funnel all those enquiries through a separate phone running an auto responder which directs them to text my main number. That weeds out 90% of the TW.
I tried CrazyOz for a couple of weeks but got 100% TWs and no bookings so deleted my listing!