Do you need to connect scart as well as HDMI lead?

I just searched for this very question as I've just experienced it first hand. My aunt has just had Sky installed after moving from a 'Virgin cable' area. She's only paying around £20/month subs but has had a new Sky+HD box installed.

She complained of getting viewing issues after only having it installed yesterday. I called in and checked connections and the Sky installer had connected scart and HDmI cable. The problem she was getting meant that the 'source' button on the TV controller was the only way to get the picture to show. Everytime the TV and Sky box was turned off, the problem returned. She doesn't have the HD package so, by trial and error, I discovered that the HDmI cable is the only one you need. This gives good quality picture on all channels and, of course, Excellent HD pictures on the few 'free HD' channels from Sky. Hope this helps