Under current discussion of "Skillicorns of Lonan"on message board see Lois Ralph's entry of May 25. Towards the bottom of the page there is information on the Maddrell family of interest.
William Maddrell (who married Margaret Skillicorn) was chr. 1788 Rushen parents James Maddrell and Margaret (chr. Mary 1755 Lonan) Callow. Other siblings of William Maddrell chr. 1788 are:
James chr. 1789 Rushen
Thomas chr. 1792 Rushen &
Mary chr. 1789 Rushen

Margaret Maddrell als Callow died intestate in 1800. See Brian Lawson's site for a transcription of the administration of her estate.

Aunts and uncles from both the Maddrell side and Callow sides of the family were brought in to administer the estate and to act as guardians of the four underage children. James Maddrell had been impressed into the British Navy in 1788. (See under Parson Clague, Rushen and impressing of Manx Fishermen) and was aboard the HMS Captain in the Caribbean. (There is a history of the HMS Captain on the Internet as well.

From the Maddrell aunt and uncles, you will be able to determine which James Maddrell was Margaret Maddrell als Callow's husband.
(Had it figured out but my computer died a month ago and I lost some data.)
A year ago an Adie Jack had a web page that included Maddrells. I can no longer find this web page and his e-mail addres doesn't seem to work any more. I would be interested in getting in touch with him if anyone knows his whereabouts.