Oooooh, those looked amazing! But... no reception...?

Correct there is no reception, I suspect the venue is run just by the two of them.
So they probably just do not have the time.
I'll quote their website:
Da wir keine Rezeption haben und wir nicht immer im Haus sind, ist es dringend erforderlich Ihre Ankunftszeit mit anzugeben.
And my attempt at translating it:
Since we do not have a reception and we are not always around, therefore it is really imperative you do indicate your time of arrival.
I am sure there will be some solution for that.
It may be as simple as a phone call.
