Our kitchen lights are switched from both the main door and the back
door. In practice, we don't need the back door switch.

What is the easiest way to convert this so it's just switched from the
main door?

I thought maybe just join the correct pair of wires behind the switch
plate? What do you do with the spare one? Just jam it into a wago
connector so it's insulated?

It's been wired in the normal way according to the wiki.

Whilst on the subject, is Adam okay? I haven't seen him posting recently.