Did you book her her augustas, £350 is massively overprices, £200 tops for a great agency girl, you need to do more research or ask for specific advice, hair colour, size, age, ethnicity, services etc....
If he got too selective, then I'm not sure he would find anyone suitable.
Looking for a English Rose type under 25 in London who's a sub type already narrows it down considerably.
If you look at Lizzy Wilde's profile, she says she is having doing incalls on September 14. So try contacting her.
I've not seen her, so can't comment, but if you don't mind a Welsh girl, then she seems pretty close to your requirements.
But, like the others, she doesn't seem to be doing incalls at the moment.https://www.adultwork.com/3191712
If money is not an issue, then just hire a room for the day and book Lizzy or one of the other escorts as an outcall.http://www.dayuse.co.uk/united-kingdom/city/london
However, the problem you may have is that as you've got no AW feedback, some escorts may not be willing to see you.
In which case, agency may be your best bet. They may take your credit card number, though.