Roy Benson is a German trading company not a manufacturer, the saxophones (and other instruments sold by them) aren’t German made at all.
Their quality is very average but would certainly qualify as a student’s instrument. Of course nobody can comment on the particular saxophone that you have been offered because every saxophone needs to be played.
If you can, have a good player or a teacher assess the saxophone for you. I wouldn’t pay more that 180£ for it and that is only if it would be perfect and assessed by a competent player or, even better, a technician.
As Jonf said, most members here would probably agree that you could buy a better saxophone, at any rate , get yourself a Selmer or Yamaha mouthpiece and start learning the saxophone.
Good luck!