I have a 20" traditional TV, its around 4 years old.
When I am watching it I can see other television programmes and adverts in the background; it is very faint but it can affect the colour of the screen.

I had satellite TV installed around 6 months ago and I can't figure out if its this or the TV dying... :S

Any help appreciated

Sounds like "Ghosting", If you are near local transmitting station, or bad shielding on coax,
May be picking up multiple channels.
I would turn sat off, unscrew coax from back of TV, then just have the center pin inserted
Without screwing in( so outer shield is not connected) Try to see picture and Identify source. May need a Trap.