I think, like me Atlas Shrugged if it's the iOS app you are running then it has to be connected via BT as ANT+ isn't an option for this OS. I considered trying an ANT+ usb dongle via a lightning to USB connector,but from what I read online this doesn't work. (apart from some questionable sounding software bridge hacks)

I could certainly buy an ANT+ dongle and run this with a laptop, but it's not an ideal thing to lug my computer out to the garage each time I want to train. It's ironic that my least favourite training app (Zwift) works perfectly apart from being annoying AF 😂

Thanks to everyone for their replies