Newbie help with ISO

Newbie help please using IOS

Hi all, hope you can help a newbie out as I’d love to get this up and running. Raised a ticket with Zwift and awaiting feedback.
So, the issue is I have cadence and heart rate in Zwift but no speed and my avatar won’t move, in the connection screen all three (cadence, hr, speed) work though!? Go figure!

I’m running the following;
‘Dumb’ Elite chrono trainer
Viiiiva 4iiii heart rate strap (bridge from Ant+ to bluetooth)
Garmin speed 2 and cadence 2 sensor (from Garmin Edge 520 plus)
iPad mini 2 on IOS 12.4.6

What I don’t understand is that I can see speed, cadence and hr in setup (selected trainer after speed sensor for the power curve) but as soon as I go to train or race there’s no speed!?

Although image shows power meter in connections this has now been set to speed prior to selecting the trainer (generic).

Any suggestions gratefully received!

TIA!