DunLaoghaire Can anyone confirm SEPA Instant works with bunq?
Can confirm. Use it all the time. Both receiving and sending.
DunLaoghaire Ideally also tried it between Revolut and bunq?
No, I don't use Revolut. But even when two banks support SCT Inst in general, that doesn't mean that it's possible to send instant transfers between them. The banks will only allow an instant transfer if they have tested it with the other bank's system and made sure everything works. Best thing to do here send support requests to both banks to tell them that the respective other bank also supports SCT Inst and that they should make it possible to send instant payments between them, and then wait.
Edit: I see you mentioned Revolut only has it for one week. Yes then it's completely normal that it doesn't work right now. I experienced the same thing at many other banks who started to support SCT Inst -- it always takes some time.