> Currently, this feature is available in the U.S. and Canada. As we roll out this feature, we will explore how we can expand this offering to outbound calls and texts, as well as to other regions.
(Edited to add:) And I feel your pain - I'm a Relay engineer in the Netherlands, and I can't even use this myself... But unfortunately, it's not easy to offer this elsewhere at a reasonable price, so we're still figuring that out.
i can't see any option when i log on from the uk.