Locked from the inside - the sashes were stuck together and needed to be cracked apart - a few gaps - I had to find the cracks and work them open before I worked the lock slowly open.
I friend showed me a way to cause the lock to “jump” the inclined part of the mechanism, which was very quick, but sometimes broke the wooden sash.
Beyond this description and I will need to seek legal counsel...
(again, this is pointless as far as the case, but is fun)
What did you use to crack the sashes apart, and work the 'cracks' open ?