OK I see what happened.
Looks like topvintage.nl is indeed part of TT UK. But because I removed all non-UK merchants from our TT UK account topvintage.nl is currently only listed under TT NL. As you probably don't have a TT NL account your links are not working.
I'll re-add topvintage.nl to our TT UK account and update this thread when this merchant is available again in the Datafeedr TT UK section.