Many HD channels not working at all ie no signal being received ie Sky1HD, Sky F1HD

Latest Silverfox channel list installed, satellite .xml updated.

When I check the tune there is no signal being received on the correct frequency for Sky F1HD for example. However many channels do work-I can get the SD F1 channel no problem, so some channels are working fine.

I'm running VIX 2.2.1.

Any ideas what to try next?