The 97th Regiment left for Ceylon in 1825, and arrived back in Gosport in September 1836. After two months they moved to Woolwich (6 months) and then Stockport, before moving to Ireland in April 1838.
Civil registration started in July 1837 and FreeBMD have a Martha Purcell registered in Stockport in Sep (qtr) 1837. Before risking £9.25 you should ask on the Lancashire board as lots of baptism records for Lancashire have been put online.
Unfortunately the 97th moved to the Ionian Islands before the 1841 census. Looking at the post from 2005 about the Chatham census for 1841, it is true that Chatham was very often the departure port for regiments going to India, and regiments would often leave their Depot in Chatham. So Purcell may have followed a few months after the rest of the regiment.
I think it more likely that Ann married in Ceylon as a widow, rather than elope with Edward. She would have had no way of getting to Ceylon under her own steam un-married. As is often the case the answers probably lie in the muster books for the regiment. They are in the National Archives (not online). They will not have any information about Ann and his children (except if the Paymaster recorded his widow receiving his back-pay). But you should get his place of birth, age etc. Plus you can confirm if there was a man called Holman in the regiment who died in Corfu.
Ken