A qualification can only be delivered by an awarding body which is regulated by a government body. The one you will most commonly see on site is OFQUAL, the government regulating body for England - but there is a different regulating body for each country in the United Kingdom, as well as the Republic of Ireland. Each regulating body maintains a list of the qualifications it regulates.
Before enrolling with a particular club contact them and ask if you can go to watch a class without your dog. This will help you decide if this is the right environment for you and your dog. Some clubs have waiting lists and you will need to book ahead, some accept people on a roll on roll off basis. Prices will vary from a joining fee and then weekly payments to a one off fee for a certain length of training.