Hi Pete,
I posted the original details that Mart directed you to (thanks Mart), we've use them a few times, as have my parents with no problems. The journey is approx 1hr depending on the time of day that you go through Murcia & your driving speed (we seem to have some Jenson Button wannabe's on the forum ). We just 'reverse' the route for the return, fairly easy, but then as I'm the navigator...... My hubby may disagree!!! On the return, remember to stay on the A7 heading north, it can get a bit confusing with all the exits around Murcia (I hope it odesn't put you off...).
Safe driving
Sara