I only recently added a few stamps to my Palestina stamp collection when I noticed that the stamp below (I think) has a surcharge/overprint beneath the cancel. However I just cannot make out which overprint this would be. Anyone have a suggestion?
The second picture is of the back of one of the 1927 definitives, the 20m value. Make those blue lines this a coil stamp? Or could this have been picked up from the postcard or envelope it was on?
Any help appreciated.

