I've just replaced the Plusnet router (provided by Plusnet - my ISP) with the TP-Link TD-W9970 & now my Sky on demand service is not working.

The Sky+ HD box is connected by a Sky mini wireless connector via Wifi to the router - they are all in the same room

The wireless & LAN setup of both the Plusnet & TP-link routers are the same

The Network status of the Sky+ box says 'Connection to broadband router OK' but  'Connection to On Demand FAIL' when connected to the TP-Link but both connections are 'OK' when the Plusnet router is used

I have put the PLusnet router back & that again works fine

The only difference i can see is that the Plusnet router has both 2.4 & 5GHz frequencies - could this be the problem?