Do I want qualification to apply for a work at a pet shop/stores? If yes, what diploma do I call for?
Answers: No qualification would be necessary but if here is someone being interviewed that have NVQ in Retailing or Sales later they would probably be preferred to someone with no certificate.
I wouldn't have thought that you would necessitate any qualifications.
But it depends how mature you are
If you are still at school you wouldn't have need of anything. If you have gone they may want GCSE Maths and English (or equivalent)
Just the ability to do makeshift math, present yourself in a tidy deportment and the ability to assist people near questions just about keeping their pets.