Denon AVR-X3600H not passing Apple TV Dolby Vision

I purchased an Apple TV 4k at the weekend and i’m having trouble with The Denon AVR passing through Dolby Vision to the TV.

The components in question are;

Sony Bravia KD49XG9005

Apple TV 4k

Denon AVR-X3600H

5.1 Speaker set up

2 x 1m MyTySun 2.1 48Gbps HDMI Cables (Amazon)

All have been updated to the latest firmware and the AVR has 4k Signal Format set to Enhanced.

When I route the Apple TV into the AVR using AUX2 input (second closest to the output) and Connect the AVR to the TV using the ARC channel (TV HDMI 3), I get 5.1 sound but only a 4k SDR 50Hz picture.

When I route the Apple TV to the TV using HDMI 2 and then back the the AVR using the ARC Channel (TV HDMI 3), I get 4k Dolby Vision 60Hz but only but only Stereo sound.

It would appear that my system will give the highest possible sound and vision but with the current configurations, I have not been able to get both together.

Has anybody else experienced this issue?

Are there and further settings I should try?

Is there a different configuration I should try?

Or any other suggestions you can give?

Thank you in advance for your help.