My sprinter wont start?

Just wondering if any of you have any idea what's up with my sprinter 55 plate (2005 313 cdi xlwb)I've just come to get in it to do a job and there is nothing there at all, no lights on dash no power at all i was in it yesterday and monday no problems with it, parked it on my drive as normal last night everything ok with it and now nothing at all, i've rung the RAC but i havn't got home start and my service guy is in Tenarife till tomorrow. the only thing i have noticed that i can think was Monday night i got back home went to take the empty pallets out of the back and my light's in the back didn't come on and wouldn't come on when i tried to turn them on. Any ideas (i've looked at the battery it looks fine and it's only 2'000 since it was serviced) it's as though the battery has been tacken off.
Can you help me please