This is very cheap for a set of rechargeable FM wireless headphones. They are made by Targa (Germany) and have a 3 year warranty. They have a comparable spec to the higher end Sennheiser RS's which typically cost £70+. (FWIW, I doubt they'll be as good as the Senny's but you are getting a heck of a lot for £20 - plus a longer warranty).
These are in-store only, and stocks may be limited. My local (Bangor) had about 6 pairs this morning, and I bought two of them! So you may need to be quick. BTW, if you get the Daily Mirror you can get a £5 voucher for LIDL (off a £30 spend) which could make this even cheaper.
Hope this helps someone.
From the LIDL site -
* Wireless stereo headphones with scan FM radio
* With a powerful 863MHz FM signal transmission, range up to (m): 100
* Charger base station with 3 selectable FM transmission channels
* Includes cables, jack adaptor and much more
* With rechargeable Li-Ion battery
* 3 year manufactuer's warranty