The first disc needs to be connected via Ethernet. The discs are intended to be used as a standalone mesh with wifi disabled on the prime router.
You can obviously still also connect to the Toob router with Ethernet to your laptop.
Factory reset the discs before trying to connect as the Virgin and Toob IP subnets are probably different.
Done this followed the app guide and when I try to connect to the main disc, it connects then unable to detect disc.
discs have been factory reset, disc is connected via Ethernet and is connected to mains, wifi is off on the main TOOB router.
I don’t know what else to try as all this equipment works from my current virgin router!!
Nor do I, I'm afraid. The problem clearly lies with the Toob router however as the discs work ok with Virgin and other providers.
Can you borrow a third party router to see if that works ok with Toob broadband (perhaps from Amazon 😉)