The regional REITs are going to run into a big problem as the laws regarding energy performance certificates (EPC) come into force in 2030. Buildings taking on new tenants after 2030 must be in categories A or B (the top two of six categories), which will require a lot of work with older buildings suh as installing new boilers, improved insulation, triple glazing, etc.
This point was raised by Marcus Phayre-Mudge, manager of TR Property Investment Trust, on the Money Matters podcast of last 15th April (link below). The cost of improving many buildings to obtain an EPC will dramatically cut the profitability of many buildings in secondary and tertiary locations.
The building where the interview was conducted was in London's West End where the rent was about £65 per square foot, compared to Hartlepool at around £8 to £12 per square foot. The cost of improvements isn't much higher in London than Hartlepool, so the costs of complying with the EPC will be far worse for secondary and tertiary buildings ("the landlord's gonna have to spend the money but isn't going to be able to push the rent up"). This part of the discussion starts at 31 minutes 20 seconds.
https://money-makers.co/2023/04/15/money-makers-podcast-15-apr-2023/https://en.wikipedia.org/wiki/Energy_Performance_Certificate_(United_Kingdom)