fitted jvc dab head unit all works fine memory the lot but how do i get it to switch off when i take the key out any help would be appreciated 

Aftermarket headunits quite often have the permanent and switched power lines reversed.

Not sure what age you octavia is but when I fitted a hands free kit into mine there is no ignition switched live present at the quadlock connector.

The stereo is switched on & off using a data signal via the multiplex (Canbus) system. So you only have 2 options:

1) Get your ignition switched live from the fusebox to the right of the steering wheel

2) Buy a Canbus decoder which will read the data signal and give you a traditional switched 12v

This is assuming you have a quadlock connector, if you have an ISO then see John999boy's post as I have seen this a lot.

Edited 23 March, 201412 yr by xpower

I fitted a piggy back mini fuse into the towbar electric fuse on mine, works a treat and is switched live, takes 5-10mins to put in!

This is what you need if you want plug and play

 

http://www.caraudiodirect.co.uk/ctssk002-2-can-bus-steering-control-adaptor

 

otherwise you need to run a cable from a spare switched live in the fuse box to the headunit. You will also need to swap the perm live and ign live over on the headunit loom