its all well and good advising somebody to smash the windows in on there car.but even taping up glass you have no guarantee how it breaks and as you can only tape the outside and you are striking it from that side i doubt that tape is gonna hold all the glass when you bash the other side of it threw with a hammer.the glass cud go inside the door like wayne said and rattle around its messy and a ballache, AA ,Auto-Locksmithor some kind of home lock breakage that dnt involve bashing ur windows threw.
how do you suggest breaking the lock? the vw boot is a good design, only way of breaking it is prob with a chisel and hammer to bust the plates, but this WILL dent the boot panel, no way around it.
drivers door is different, you can smash the plastic clip off and get to the latch, but even this way youll prob do damage.
window taped up and hammer is the safest bet and cheapest option. just price up window you decide to smash first. if you tape it up properly then you should be good, sellotape holds very well, done it before and only had a little mess to clean up.
get a 2nd central locking fob made up and keep it in the house, even if you get locked out miles from home just get someone to blip the key into a phone during a phone call and itll unlock your car!
and ive never ever heard of any car opening the locks when you disconnect and reconnect the battery, ever!