Thanks Adam.
Yes, I had tried the reboot of all three over the past week with no luck.
TBH I think the router is somehow getting in the way but I don't know how. All our devices around the home, 2 laptops, 2 iphones, 2 android tablets, 1 printer, apple tv all connect to the wifi and subsequently the internet but I can't see the devices within Time Master.
Interestingly the other day I disconnected my printer and was then unable to locate it to re-add it though I could still print to it via the cloud and scan and email so it was definitely connected to the wifi. I have though just now been able to re-add it and print to it directly so whatever was preventing the printer from being visible has rectified itself. Whilst troubleshooting that I first noticed I was unable to synchronise Time Master.
So whilst I accept that the root cause is probably not with Time Master, the current symptoms are and I was hoping your experience might help me identify something further to chase down.
Any thoughts/suggestions would be greatly appreciated. I've kinda hit a brick wall at the moment.