Replaced the battery on my Dobby, now I can't get into the boot (single door upward opening)

I can see the lock twitch when I click the fob to lock/unlock. All the other doors work.

The key won't open either.

Any Ideas?

Okay, further inspection has revealed the incidents are not related. Just a coincidence they happened on the same day.

The problem was caused by a small coil spring which has rusted through and snapped, failing to return one of the levers from the boot handle. I was able to bend the remaining part of the spring enough to fix it.

This is all accessible through the boot panel. The mechanism is fairly simple to take out, once you unhook the servo and connecting rod for the catch.