Vector Victor,
As an experienced Instructor/Examiner and having several years ago set up and run my own sizeable Flying School, I am appalled.
The Owner/Operator does not deserve to be in business. Please do the right thing and call the CAA on 01293-567171. Ask to speak to training standards and the inspector who checks this School.
Mad Jock made a very good point about the Insurance aspect. If non qualified personel are carrying out trial lessons it's simple. THERE IS NO INSURANCE!.
It is your duty to protect the public from this type of operator, or you may have to live with your conscience should an accident arise