Have updated the Hauppauge software from 2.5e to 3.4b (a bit of large jump). Rescanning channels worked fine, with a slight hicup in the renumbering.
Attempting to watch any DVB-T TV channels gives an interesting bug: a large chunk down the middle of the image is covered up. The covered up area is the same width as the now/next overlay, which itself appears fine.
Primary was set to "Allow VMR", "Either" type. Changing this to "Allow Overlay" solved the problem. Changing back to "Allow VMR"/"VMR7 Only" also solved the problem. Picking "Allow VMR"/"VMR9 Only" caused the system to hang solid (oops). After restart back to "Allow VMR"/"Either" and problem is back. Trying "Allow VMR"/"VMR7 Only" fixed it.