On the strength of Pippunting's review,
https://www.ukpunting.com/index.php?topic=190489.msg1982158#msg1982158, I decided to give Janice a try. I was holed up in Heathrow so she was handy, and I liked the "oral" extra which seemed to indicate a bit of more adventurous HE approach. His description is pretty accurate, but the overall experience was pretty disappointing.
I arrived and asked how much for 1 hour and she said 60 (which is what the previous review noted). A bit pricey as most massage is about 45 per hour in the area. I asked about "extras" (my fault for being vague -

) and she said that would be another 30. If HE is standard 20, then 30 for oral seemed reasonable and I was thinking that maybe I could wrangle a bit extra like B2b.
She started with the obligatory massage which was really mediocre. Not much pressure and lots of long strokes just rubbing the skin. The one thing that was good was she kept spending a lot of time on the outside of the hips with solid pressure by the thumbs. At my age, my hips do give me a bit of gip and this part was really good.
I started enquiring about the extras. She shut down B2b immediately like it was out of the question. She took off her top revealing 2 bras (?). I asked about oral and she said "never on the first session". So she did the HE. It was okay but nothing special. She did lower the bras for me on request.
After HE, she carried on with a bit of massage. Several calls came in which she took (though she did apologize). Then she said "the hour's up". I got up, checked my phone and 45 minutes had passed.
So, 90 pounds for a so-so 45 minute massage from what Pip described as a "6" looker, bog standard HE. Definitely, not worth the money. There are plenty of cute thai women doing strong massages for 45 an hour with 20 for HE. The chance of getting a bit more with Janice is highly unlikely.