Certainly not talking about weeks notice to book! A couple of days at most probably, but as I understand it same day bookings are possible, depending on what is already booked, obviously.
As for PSE I don't really know what you want from that, so can't advise much there. Natasha is my favourite girl, and I wouldn't let the lack of reviews this year concern you there - I just don't report on every visit like some! I certainly wouldn't hesitate to recommend her though. As for Anna, I've never met her, but I respect the others here that have, so I'm sure you wouldnt be disappointed there either.
Of the 2, I think Natasha offers the wider range of services, so if those fall into your idea of kinky, I'd suggest giving her a call and seing what you can arrange with her.