Not sure how helpful this is but I’m 5’4″, have a 16″ inbred but with a backwards lay back seatpost and a tiny stem, as its too big.
Now have a 14″ scandal too, perfect!
If it makes any difference I road a 17 (or 17.5″) framed Specialized Myka which seemed to be a pretty good fit too.
I’m in Nottingham for the next 2 and a half weeks and then back in Northampton after that, so probably a bit too far from london to actually try it out.