Unfortunately "Bakerloo, Circle and District lines" only narrows it down to two sets of platforms and my knowledge isn't encyclopedic enough to know which one platform 3 is.

Although exploring the map a bit more, it's clear they're Bakerloo based on https://www.openstreetmap.org/way/953121079#map=17/51.51706/-0.17436&layers=N .

I've also found the root cause of the issue:
https://www.openstreetmap.org/changeset/127273558