I was a newbie once. Here's the thing you need to know:
Its better to give first before you receive.
......use the reviews to decide for yourself and then do a review and then come back and ask some questions.
That's ideal HW, but at the very least if looking for a first punt a newbie should do some basic research before posting asking for advice.
London is a big place with literally thousands of girls to suit all tastes. So do a search on AW for the services you want, any physical traits, and then distance from your postcode. Once you have a list of girls, search for them on here - use their AW ID which is the number in the URL at the bottom of their profile - e.g.
Link to this Profile Page using https://www.adultwork.com/69696969 or https://www.adultwork.com/Perché_Takes_Big_Cocks
Simply put that number in the search bar at the top right here on UKP and see if they have any reviews/comments. If not, ignore them and move on. Repeat for all the girls in your search that you like the look of.
Once you have done a bit of homework and come up with a short list, then maybe ask for some advice. Honestly though only you can decide who to see - so having read reviews you should be able to make your own mind up.
Otherwise when you ask us to shoot, you're going to get shot down in flames.