pretty sure Openrent won’t transfer deposits to some other scheme - dealing with the deposit themselves is part of the deal when you use OR to create the tenancy
New LL (wife).can simply nominate current LL as an agent to deal with deposit for them and there’s no action needed, don’t think there’s any RRA breach if they do that? What would the breach be if they do that?
Re burdens- if LL proceeds with new tenancy they can tell tenants to ignore OR chasing and pay new 1st month rent on date due and pay new security deposit only when old security deposit has been received - these don’t need to be paid upfront at all. The only cash flow issue for tenant is providing the 1 week holding deposit and again this could be avoided or minimised by accepting the application for new tenancy/holding deposit and doing the new contract on the new contract 1st month due date (or very shortly before). (If need be the holding deposit can be paid in OR by a third party so LL could pay it and get back from tenants later by them paying the normal full monthly payment amount on the due date for the new contract)
Doubt any new vetting for RGI needed when same tenants continue on same terms. Why would an insurer need any new vetting?
It’s no more or less paperwork than when a LL moves tenants onto (or off) the Openrent contract- when a new contract would be normal.
Agree it’s not ideal that OR basically don’t support change of landlord with no new tenancy contract despite these being possible legally with s3 and s48 and deeds of variation - but nobody is forced to use OR, and there are some benefits to tenants from using OR too (deposit properly put in a scheme, £ handed to LL 10days after 1st payment due date to protect against rogue LLs, a standard contract)
Best

