Sorry, this is long, but hopefully some points are helpful.
DH and I have a property which is now rented to students. DH is more involvement around the legalities though, hence I don't know every, single detail.
-I agree with checking if there is even demand in your area. In ours, the uni has built a huge amount of student accommodation, so we almost didn't get it rented out this year.
-We enquired with local estate agents, but the uni have their own student association thing. They act as the estate agent, can organise plumbers/electricians etc and the fees were less than the estate agents. Another plus is that they inspect through the year, and if the property is left in a horrid state- the students don't get their degree! I don't know if all unis have this though?
-My understanding is that an HMO needs additional regulatory requirements and locks on each bedroom door. So each room is rented individually, whereas we have always rented to groups of friends- who sign1, single contract. Sometimes, the uni people have put groups together, but because they are renting as a group, not individual rooms, I 'think' some requirements around HMO's are different.
-Check the bedrooms and common area requirements in terms of size. We had a box room and a very large master, but the box room was too small to be classed as an adult bedroom. We moved the wall over and both rooms could be rented.
-Also check on minimum common area size. I 'think' this was a change in the council the house is in, not UK wide. We'd rented the property 4yrs, when they changed their requirements and said the common area was 1.5m2 too small! We'd either need to re-configure the bedrooms to make them smaller, to add more common area space, or add an extension! In the end, we added a conservatory, but it was a PITA and an expense we weren't planning on.
-Again, suddenly after 5yrs of renting, they changed the rules in terms of the kitchen. Each student needed their own kitchen cabinet, own fridge shelf and own freezer drawer! We managed to find a kitchen cabinet that reasonably matched the rest of the kitchen, but also had a buy an additional freezer- despite already having a very large fridge/freezer.
-We have to provide a bed, desk, chair, wardrobe, bedside table in each room. Divan type beds last longer than slatted/cheaper ones. Always provide mattress protectors. We also bought cork boards for each room. Prior to that, people would stick blue tak and things on the walls. The cork board helps prevent some of that.
-We don't provide a toaster, kettle, bed side lamps etc. Each item will require pat testing each year, which WE pay for, so try to minimise electricals unless required.
-Our contract includes a gardener. I'm yet to meet a group which would mow and manage the garden themselves!
Overall, its been a positive thing. Most groups have been ok. DH and I had done the property up to live in it ourselves, new bathroom/new kitchen etc which I think this helped. Due to changes in my work, we stayed living where we were though. If it started out run down and old- it would likely have been left in a much worse state than it currently is. Happy to answer any questions you have.