Based on a recent thread, I think it would definitely be great to see OVO to officially support Relay UK and SignVideo services, such as by listing them at https://help.ovoenergy.com as an official contact option.
SignVideo should be as simple as posting the link to start an instant call, while Relay UK would be as easy as saying speech or hearing impaired members can call 18001 0330 303 5063. Or you could potentially add a special number that’s dedicated to Relay UK users which can skip some of the automated IVR stuff and go directly to the queue.
Another forum member tried out the Relay UK option the other day and it worked brilliantly for them, so that’s evidence that OVO can definitely make it work too. :)