Falz.
Like most things in life, you get what you pay for. If money is no object, one of the major schools like Oxford has the fleet size and experienced instructor force to give you gold-star training. If you're working to a budget, somewhere smaller gives you the same qualification but you may be fighting with others for the one FI instructor and a limited number of aeroplanes. I suggest you look at the available FTOs, make a shortlist and visit. Chances are if it feels right, it will be right for you. Good luck.