I'd have to add that with free porn on the net, the only places I can think of where one might spend similar (10 quid, not 300!) would be a live 1-to-1 webcam chat/show with one person (or a couple, or 2 girls, depending on what s/he as customer wanted).
Someone earlier suggested that the use of a phone chat service was "more personal". It might be considered so, but given the shortness of a call, and the 'dolly bird' being in London, then to me that's hardly personal. Had he been to a pub with strippers, or a lapdance club, where one would be in touching distance, and perhaps arrange to meet outside their environs, it would be different.
There are live webcam shows from outside the UK which have few banned activities, and no Ofcom-required censorship, unlike anything on UK TV - I don't think even the encrypted adult channels are allowed to include what's on the web.
Admittedly 10+ years ago, when shown on "The Adult Channel" or "Television X" (I had a pirate card!) "Debbie Does Dallas" had a good 30 minutes cut {I had seen the original when I was in my 20s when Beta and VHS were still common}. What did they cut? Plenty, so no erect males were shown at all, and I think most of the explicit scenes with candles or vibrators showed very little.
I'm not meaning to 'downplay' this as I'm male, but to try to put it into perspective, and had thought of a fetish angle such as midori1999 alluded but hesitated to suggest he might want to have fantasy [or activity] which you'd never want to participate in...