Ring pro losing connection within a few minutes

Hello, my parents had a Ring Pro installed by their electrician a few weeks ago but it keeps losing its connection to their Wi-fi. They also have two Ring cameras and both work fine. Their internet is with BT from a smart hub. They spoke to one of your customer support colleagues who said the presence of a 5GHz network was the problem (which is ridiculous) so I switched this off (leaving only the 2.4GHz network). The problem remains though, it will connect initially and work fine but within minutes the connection is lost. Device Health reports good power and good signal strength for the few minutes it remains connected. I have changed the channel twice and ensured it is between 1-11 as I noted this can be an issue in a forum elsewhere. They don't have many devices and live in a rural village so not many nearby networks to cause issues. Please help ASAP as it is a real issue to have them unable to hear their doorbell...