i've purchased a 2005 Panda, with the remotes dead.
is there a method i can use to open the boot (i understand it is supposed to be electrical) without using the key?
Make sure the car is unlocked. The handle is right above the license plate, between the license plate lights. It's a purely electrical switch which actuates the exact same mechanism as the boot popping button on the remote.
Even if you don't replace the switch, you may find that by following the guide you can get to it and clean out any dirt/grit which is preventing it from working