Thomas and Catherine are 1851 Census records living in Deptford Kent. He is a shipwright aged 36 and she is 32. The place of birth for both is Douglas IOM.
The IGI has no christening record for Thomas. However, Brian Lawson's site (www.lawsons.ca) has two dissenting births in the 1820s for Readys, but not for Thomas.
The IGI has two possible Catherine christenings:
October 17, 1817 to Robert Kelly and Catherine Christian
Nov 20, 1819 to James Kelly and Elizabeth Sayle
In 1851 Thomas Kelly 26 visitor, labourer, b. Douglas IOM, was living with the Readys in Kent.
The only Ready family that I found in 1841 is that of General Sir John Ready, Goveror of the Isle of Man from 1832 until his death in 1845, and his second wife Sarah Tobin. He had children from a previous marriage. However I have no evidence that he and his first wife, Susanna Bromley ever lived on the island.