@Iw I think there are some good points there.
I think most commercial rents are reviewed every 5 years.
There was some mention at the T&E Committee that a couple of shops were up for review and the 'uncertainty' meant that people might not sign a new lease.
Rents seldom go down, because the property owners have a vested interest in getting as much rent as possible. They may even find businesses that think they can be more successful than current ones and therefore willing to pay a higher rent.