Renting a room is about mutually benefits. When a hair salon rents out a room to a beautician it can benifit both the salon and the rental. We pick clients up from them and vice versa. They might feel your clients might not filter through.
It could be the position of the shop, not a busy street etc. Could be the price or the decor.
If the tanning shop is busy, why not put another bed in the room, it'll make you more than £50 per day.