You can still register for #MarkupUK (June 1–3) and attend in person or remotely: https://markupuk.org/
The remote option doesn’t comprise the tutorial day though (neither does it probably comprise the social dinner including the #Demojam).
Five of us will be traveling to London, of course by train, and @xporc will give a talk on Friday June 2, “Bridging the Gaps between XML and LaTeX.”