Ok, so an update here.
The issue seems almost certain to be an issue with the Meraki Go AP itself.
The Sky Q boxes are designed to transmit on both 2.4 and 5Ghz, although it seems they prefer 2.4Ghz on first bonding.
With the GR10 hosting the SSID, the sky box connects, then after approximately 5-7 minutes the SkyQ boxes disconnect, claiming they cannot connect to the network.
The only way to re-establish is to wipe and reconfigure the boxes and rejoin the SSID with the password.
After a further 5-7 minutes the Sky Q boxes lose their connection again.
This clearly suggests the Sky Q box performs some action that causes it to become disconnected from the GR10.
Host the same SSID (and same password) on a Cisco SMB (RV Series) Router/FW/AP, same IP range, same VLAN and the connection remain stable and doesn't drop.
GR10 is on Channel 11 & 44 but the RV is running 6 & 36
All other devices are super stable on the GR10 (iphones, microsoft devices etc...) it is just Sky Q boxes.
Without the capacity of the Meraki enterprise devices to perform packet capture, manually adjust channels etc... can't diagnose further.