Battery dead after a 2 weeks in the garage

[lurky]

Hi
I recently posted on here about storing my 2007 boxster for the rest of the season.
What I came away with was that the best plan was to just garage it, and start it up every other weekend to keep the battery charged.
I tried to start it up this weekend and the battery was dead. (its a fairly new battery)
So now I've bought a trickle charger and my plan is to start using the car again in three weeks, so Im thinking about taking the battery completely out of the car, and start the trickle charger in 3 weeks.

I was warned to not remove the battery from the car before because i would loose some information in the memory but that's got to be gone by now anyway.
Is there any downside to my plan? Thanks