On Saturday, March 24, 2012 12:31:10 AM UTC-4, Philatasaur wrote:
I have a few of these stamps, with what appears to be St John
Ambulance hand stamps applied over.

Any idea what they were used for, and what are they worth?

Any help is appreciated

It is very difficult to help without a visual aid to understand the question. If you don't have a web site of your own, post it on cjoint.