Looking for some insight on how to do a retrospective RPZ review for a relative who has a 2 bed apt in west Dublin. Long term tenants have just vacated as they wished to relocate to their home country. Their first rent was set at 800 pcm in August 2011. It only rose to 825 in August 2014. They were good tenants and he was an obliging landlord. He has spoken to the PRTB and they advise that there can be rent increases beyond the subsequent ones that he started to do annually from August 2018 when rent was increased to 1100. Any thoughts ?