I messaged Roeland on the Hivefest Telegram to say you were looking for a refund.

I just checked my NHS app to ensure I have all my vaccination barcodes. I'll carry a backup copy of those just in case. I think I am sorted to go next week anyway via Eurostar. It would be great to see you there if you can make it.

Update: @roelandp said:

oh ok too bad there is zero covid crap policy here in NL. only stupid things is direct flights from non-schengen which might require some doc upload prior to boarding. tbh its lame as f. there certainly is 0 issues when coming via belgium. earlier i tried to call him but his UK phone didnt work.

if u have any means i see if i can make him decide otherwise or alternatively refund ofc.