Many buy to let landlords are feeling the pinch of increasing mortgage payments, so either rents go up to cover the shortfall, or they sell up and pay off the mortgage.
Comes a point where it is a better return to pay of expensive debt, and also remove the risk from exposure to potentially higher rates and to bank dwindling and uncertain profits
I have a friend in exactly that situation in London, his property has been up for sale for 6mts with barely a viewing , let alone an offer. So he has just dropped his asking price. There you have it, one less rental home available and one property for sale with a reduced asking price