Mercedes-Benz SLK-Class - Battery drained after holiday - Martin Freye

My wife's SLK 350 had a flat battery after only 2 weeks in garage, (Holidays) all appeared to be switched off, car locked ( Locks itselfr after a few minutes anyway ) had a new battery 23 months ago from Halfords (£123!). Halfords have tested the battery and it's OK. A recent damage repair necessitated replacement of the front bumper, grill and headlight assembly. Previously no problem being left in garage for 3 weeks! Any ideas welcome.

Mercedes-Benz SLK-Class - Battery drained after holiday - elekie&a/c doctor
Can't see any connection to the front body repair.No real issues with this model with battery drain problems.I assume this is a W171 type.Never been a great fan of halfords batteries.How did they test it?Unless it has been fully recharged correctly ,I suspect you will have further problems.