I also think London is a relatively easy Consulate.
But part of that is because the cases tend to be easy for the Consulate, I do not recollect seeing a London one meet case, ever. So I have nothing to compare it with.
So to expand on my thought process if you are a CO and you handle K1's and have seen hundreds and are used to see loads of visits both ways and here is a recent photo of us together and it is all ticking boxes and then you out of the blue get a well we met once and it was a long time ago, is it not going to make you go huh?
I like making cases easily approvable.
And so far do not understand why there is an issue visiting.