Tvheadend

Hi

I am running A Synology DS1513+ with TVHeadend Build: 4.1.1566 and something annoying has started happening recently. I use Kodi as a front end and noticed the EPG was randomly showing EPG dara for some channels and not for others. Initially I thought it was Kodi related until I took a look at TVheadend and noticed that there was in fact EPG data missing. For example time now is Sunday 12:57 GMT and BBC one HD has EPG data starting from Sunday 18:35. As a result there is currently no EPG data for BBC. This is the same for allot of channels.

EPG Grabber Module is set to XMLTV. Interestingly I have noticed that if I go into channels and edit BBC one for example, If I unset "Automatically map EPG Source" and then try and select an EPG source from the drop down, their are no options in the dropdown. Its blank.

Would anyone have an recommendations on how I can fix this?
Thanks