No Apple Pay (Pay) showing in iMessage

Hello

Am in the UK, and trying to send some money to a friend.

The Apple Pay (Pay) button is not showing on iMessage for me to be able to send money to friends.

I have Pay set up, and have used it successfully several times I have my bank debit card registered. I'm on the latest iOS version, have the 2-factor authentication on, etc. I have an iPhone 7+.

Not sure why this service is not available on my device. Any tips?

(Please do not just send me the Pay page about setting up your iphone for Apple Cash or Apple Pay, as I have clearly already done those things, thank you.)