Dont get your hopes up about getting into the mounted police. I looked into that a few years ago and after your initial training, you have to be a police officer for a certain number of years, then after passing what im told is quite a hard riding test the only way you can get a position is if someone retires, because they only take a certain amount of people. As you can imagine, its a highly sought after role. Im thinking it would be hard to run your own riding centre whilst working in the mounted police, as well as your hours you spend working, theres horse care to do, horse training, cleaning tack ( they are VERY particular about this, you need to be able to see yourself in your shoes sort of thing) often this starts at early hours of the morning and in afternoons also...
Although, i could be wrong, This was a while ago when i looked into it. But if its what you want to do, go for it.
As for the riding school part, you will need to get an EA qualification to teach. This is a big issue. Often i will only use an EA qualified instructor, unless i know someone personally, seen them ride/compete, and they teach well. < This is rare. I think its a big one for parents too, if i had a child i was sending to lessons id want to know whoevers teaching them is qualified to do so! There are many people out there that dont know what they're doing. Also often non horsey parents dont know what your teaching their child is wrong or right.
What type of riding were you hoping to teach? Were you wanting to focus on one main area like dressage or jumping? Or just lessons generally..
For me, what i'd look for when choosing a riding school is the teaching mainly. I have no problem going to someones house and getting a lesson in a paddock if they are a great teacher and im getting value for my money.
As far as facilities go, it doesnt have to be flash, just safe. Safe fencing is a big one. Its always nice to have a large indoor arena, although outdoor ones are fine. um..would you offer agistment? If so, you have to think about the size of the property, fences, water, feed. Although im not fussed with stabling, many people are and you'd need at least a paddock shelter in each paddock. Stable blocks are expensive, so if it was me i'd start off small, with the basics for the centre then as it grows consider expanding and putting in such things as stable blocks.
You'd need staff to care for agistment horses, school horses (thats something else you'd need) staff for property maintenance.
Also, starting a business like this depends on the area. Is it a big horsey area? Would you get enough business? Are there many other riding schools in the area?
Sorry if i jumped all over the place with that, hope i got the main points across lol..