Unless that information is outdated, this is what is in the bottom of geocheck.org about hosting:
Hosted by Ground Zero Communications AB (owner of Project-GC)
Their IP points to CloudFlare which also fronts project-gc.com
https://search.arin.net/rdap/?query=104.27.186.8
To my knowledge, Ichicken is still officially the administrator of geocheck.org (and its Danish sister site geotjek.dk). It may very well be the case that he has not been online for quite some time. Unlike project-gc he has not charged anything for the work he has done. It is on a pure volunteer basis.
Being a programmer myself, I can easily see why he might decide to pull out of doing active maintainance on the site for any number of reasons. Especially the part where doing user admin is often a manual task. I respect that decision.
The question more or less boils down to: Is the site usable in its current form without an active admin? I would argue yes. Others may disagree.