The isle of man mark (the three legs) is Joseph Tyzack and Sons, whereas the elephant mark (NonPariel) is William Tyzack (his brother) of Tyzack sons and Turner. The Abbeydale works, they had secondary product line called "Abbeydale"
A good summary of Joseph Tyzack can be found here http://www.wkfinetools.com/hUK/TyzackJ/jTyzack-index.asp
and the book from which that info is sourced "Glass Tools and Tyzacks" by Don Tyzack
A bit more on the Abbeydale works (Tyzack sons and Turner) is here http://www.tilthammer.com/bio/tyzac.html
As to dating, one of the reasons for starting this site, was to build a database over time of information, like medallions, that might lead to more accurate dating.
Your saw, as a wild guess at a date I would say, the second half 19th Century.