No necessary to loose the dash controls. You must be one of the few that still use them that is if you can see them behind the wheel and they do what they are supposed to do which is rare.
You will need a headunit that has the input jack to accept an interface lead and you will also need the lead for the D1 ISO connection, match the two and you are on to a winner.
Look on Ebay too - they have a aux for some discoveries that allows you to fit an ipod - it `tricks' the unit into thinking its a cd unit and so you get good quality sound. I've just ordered one.
Here at LandyZone we have plenty of very knowledgable members so if you have any questions about your Land Rover or just want to connect with other Landy owners, you're in the right place.