Antique trick padlock help

[saxoo]

Dear all,

I aquired this lock on the attached photos recently, I'm particulary interested to date it, maybe to narrow the country of making and to know its approx. value. The little door covering the keyhole is opening with a slide trick, the lock itself works well and can be turned twice to lock/unlock.Its a huge and weighty item with ~15cm in length and ~0.5kg(I dont have it at the moment with me,will update later with precise measures).
All infos are much appreciated

S