Was denied LHR upgrade at t-37, but the flight went J0 shortly before that, so figured it's full. On the morning of the flight, noticed it went back to J1. Plat/Lumo checkin at HEL upgraded me to that without hesitation.

Interestingly, the agent at the desk had to ask me to show my vouchers on the app to confirm I had them. But that's good old AY IT I guess, might be related to why they've had such trouble for last minute upgrades with loyalty instruments.