Here is a direct quote from the tv licensing web site at
http://www.tvlicensin...is-not-needed-top12/.
"It makes no difference how you watch TV - whether it's on your laptop, PC or mobile phone or through a digital box, DVD recorder or TV set - if you use any device to watch or record television programmes as they're being shown on TV, the law requires you to be covered by a TV Licence.
If you don't use any of these devices to watch or record television programmes at the same time as they're being shown on TV - for example, if you only use your TV to watch DVDs or play video games, or if you only watch programmes on your PC after they have been shown on TV - you don't need a TV Licence. If this is the case, please let us know."
Note you are expected to declare your use of your TV to watch DVDs only. Detectors can be used to see if you are actually watching a TV transmission. They will check. And experience says you will get hassled regularly so I think you have to decide if you want to put up with that or just pay the fee.
Cheers.