I can't update my Apple Watch Series 5 because it has been reset

Hi guys,

I bought a second hand Apple Watch series 5 that arrived with the previous owners details still saved.

Did a reset to wipe that information and pair it with my phone. But when I tired to pair it says that it needs an update and trying to do it through the phone continually fails.

I can’t do it through the watch because it has been reset so the settings aren’t available until it’s paired.

Does anyone have a fix for this? Many thanks!

[Re-Titled by Moderator]