@Adriena Daunt the new or refurbed studio ones, you need to make sure they are council consented to be multiple room dwellings as with the new tenancy laws possibly coming in if the council has it as a large single dwelling but you are renting it by the room you might (you need to check case by case) fall foul of this rule that you are renting an illegal dwelling according to what is on the paperwork at the council and then potential refund rent, pay exemplary damages, have trouble with insurance and/or finance etc all come in to play. Under 5 rooms and with single only occupants on multiple leases there is a bit of room to make it work but you need to understand the risks of it not running right.
Feel free to PM me if you have specific cases you want to have a chat about and I can give you a heads up of what you're looking out for those and future ones? It is the same issue nationwide just not so well policed maybe?