Zwift app Bluetooth connection from an ipad

I have an ipad running IOS 14.3 and a Saris H3 trainer. Rouvy and RGT run on the ipad and connect quite happily via blue tooth to the trainer. For some reason the Zwift app won’t connect to the trainer. What do I need to do?

Make sure the trainer isn’t connected to anything else.

Settings > Privacy > Bluetooth: Enable Bluetooth for Zwift

It isn’t connected to anything else.