Adult renewal from US. Applied online, and requested to send old passport to Durham.
I was actually impressed with how easy this was (the online application was very simple). The biggest delay was between my old passport arriving at the Passport Office, and them actually acknowledging that it had arrived. Other than that, everything was pretty fast.
(* items below are my annotations)
*Received in US (via DHL) 26 April 2022
Passport printed 10:41am on 20 April 2022
Application approved 4:44pm on 14 April 2022
Documents received 5:07pm on 12 April 2022
*Documents signed for in Durham, 8:44am on 25 March 2022
*Documents sent to Durham from US, 18 March 2022
Application received 7:38pm on 18 March 2022
Application submitted 7:38pm on 18 March 2022