A bit clearer post than mine above...

...

These will play cds and dvds,
but only have a 2 hour play time from the internal batteries.
(they can then be recharged slowly? from the 12v socket or at home 240v)
www.ebay.co.uk/itm/New-7-5-Inch-Portable-DVD-Playe...G-

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The other route is to get a cheap mains cd player (boom box)
eg
www.tesco.com/direct/tesco-boombox-with-cd-fm-radi...1


and a 12v to 240v inverter
(just make sure the inverter's wattage is well above the cd players (it'll say the wattage on the back of the cd player)
eg
www.ebay.co.uk/itm/Car-Power-Inverter-150W-12V-DC-...5
and just use a 3 pin plug to power a box standard , mains home cd player..

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if you fancying tinkering..
there are some regulators from 12-15v down to 9volt , 2a, 3amps
which you could power straight to the battery case.. (eg, if 6 C batteries)

just some ideas... to start the stones rollin' ;)

Cheers
Liam

Edited by liammcl on 01/10/2016 at 03:31