Your Milner safe probably weighs about 70Kg, certainly no more than 100Kg. Banded safes are a bit heavier than plan ones, can’t say I’ve dealt with such a small banded one. Milners have a number stamped on the front, top edge adjacent top hinge. The number can be used to date it on this site. Does the safe have plain rectangular bolts or wedge shaped ones? Upload a couple of photos for us.