Surface Laptop 5 Thunderbolt display not working

We have 2 Surface Laptop 5's in our company and neither are working with a Thunderbolt display. They worked for an initial 15 mins then when disconnected for first time have never come back to life. The Thunderbolt connection is charging the laptop and connecting to the keyboard through the monitor, it's just the display is not coming on. We have:

- done all Windows Updates

- done all Surface updates

- run the Intel driver update tool

- run the Surface Diagnostic

- cleared the Display cache

- ensured the cable/and screen work with other laptops

- tried both rolled back and updated display drivers

We have 3 Surface Laptop 4's in the office and all work fine with the same monitor/cable so this issue is just for the 5s. Please anyone have any ideas? Thanks!