Have left my 2005 4.4 V8 HSE for 3 days without starting. Went to drive it this morning, would turn over but not start. Lots of error messages on display screen. Also, engine kept turning even when ignition key turned back. Strange! Will put battery on trickle charge tonight to see if it's ok in the morning. Hoping that will sort it. I have read on other posts that the rear tailgate switch can be to blame. My upper tailgate doesn't work so maybe?

upper tailgate switch was the cause of my battery drain remove the rubber cover off the switch and see if the contact bar is corroded if so new switch on charge your battery this could be the cause

Just replaced mine. Battery drain co-incided with the upper tailgate stopping working. New switch has it working fine again but not left it long enough to know if battery drain is cured. Get the new switch off ebay and it's only about a 5 minute job to change switch yourself.

on the case... Out of interest have a Varta battery fitted at present, local battery dealer suggests an Exide for better performance. Will check that after tailgate switch replacement.