We have a Margaret Maddrell (my ggg grandmother), christened Rushen Dec 10 1786 m Alexander French in Rushen March 4 1809 d. April 17 1872.
Her parents are possibly Thomas Maddrell and Catherine Keig. Her siblings would be William c. May 4 1789, John c. Jan 25, 1792, Thomas c. March 16 1796, Elizabeth c. Dec. 30, 1798 & Jane c. Oct 23, 1802
Her daughter Agnes French married John Christian (also from Rushen) in Liverpool in 1840.
Alexander was steward at the Kentraugh estate. This is a mile or two east of Port St. Mary. I hope that this helps and that you find a connection.