It's about 2 1/2 foot high, 2 foot wide and I can't even move it, let alone lift it up three flights of stairs before using it to destroy the patio, so I'm ruling that one out.
Thermite / dynamite etc, a little risky give the above and the fact it's sitting in the foundations of my house.
Freezer is too small.
Don't have a stethoscope, nor access to a friendly doctor.
Might squirt some 3in1 into the lock tonight and see if that frees anything up. The thing to the left of the key looks like it could have been a handle at some point but has broken off. I haven't been able to get it to turn, but will attack that again this evening.