Do you own your flat or is it rented? Just thinking the landlord(s) may not be pleased if you 'damage' the patio. When I saw NfkDumpling's post I immediately Googled 'camping driers' because I would like one in my concreted back yard - but it's too windy here for such flimsy affairs.
Have you solved your problem yet?
Hamnet am I the only reader who isn’t over the moon with it.