And about 6 seconds for me (Win 10, Chrome, sluggish VPN). I have sometimes found MS Edge or Explorer a bit faster than Chrome, against the usual trend. I detect a whiff of Minimum Viable Product and Agile over all of this, which could explain temporary oddities mentioned by the OP.

I recently had my laptop updated after 4 years hard labour on the previous one, which as you can imagine has been around the world many, many times along with the typist. My rural home broadband also was improved from 1.5 Mbps to the dizzy heights of 2.1 Mbps, which makes me the envy of the few neighbours that I have. These two events greatly improved BA.com for me and meant that I can only make 1 Flyertalk post between BA.com button presses, instead of 2 or 3.

I keenly await Boris' superfast 30 Mbps to the more rustic corners of Northumberland by 2025.