Recognised for what purpose?
For the purpose of qualifying for a specific vocational profession e.g. healthcare professions, law, engineering, teaching, etc, this may vary though. Since many of those professions in German I gather are tied to specific state examination processes a UK degree may or may not meet the requirements to qualify there alone (particularly for teaching i.e. school teaching I gather there is a fairly specific qualification process there).
Briefly googling it seems universities are only listed if someone has applied for recognition and they have reviewed it. So if it's not showing it just means they haven't had anyone submit their degree from that university for review. It doesn't meant it wouldn't be recognised e.g. for visa purposes.
I'm pretty sure for academic purposes e.g. a masters/PhD they will generally recognise a valid UK degree as most UK universities align with the Bologna process and have ECTS credit value equivalents for modules taken (as well as the degree itself).