Back to JC the Convict, and specifically to the evidence from WO97 that he served in the RHA.
The master index of miners that the Durham Mining Museum made (mainly) from the 1881 census includes entries for Clishes called George (3), Jeremiah, Joseph, Matthew (2), Robert, Richard (2), Thomas, William (3) -- and five Johns. One of the Johns catches the eye, because he was born Woolwich ca.1806. That PoB, given the presence there of the famous artillery arsenal, when combined with the fact that he had come north to work in the Durham mines and was enumerated at Heworth in '81, looks like strong circumstantial evidence that he was a son of the WO97 John Clish -- who, it seems, later and coincidently became [re-?]acquainted with Woolwich via the occasional glimpse from the decks of a prison-hulk. The census ref. given is RG11/5029 fo.116 p.2.
(One might pause to note in passing that the 1881 John looks like one more of the tough and courageous old men who struggled on with hard manual labour rather than lapse onto parish indoor/outdoor relief, pre the start of L-G's state contributory pension scheme.)
So, off to quiz the IGI. Nothing at Woolwich. However . . . there was a John Clish (only candidate ± 2 years), son of John, who was bapt. Ringmer, Sussex, 15 Sept. 1805. And a little Googling reveals that the RHA maintained a barracks at Ringmer. Exploring the IGI batch (J148331) further discloses two more children, William Clish bapt. 9 Sept. 1804 and Richard Clish bapt. 10 May 1807.
The mother's name rather thickens the plot: in each case it is Elizabeth, not Frances. But the Newburn marriage of 11 June 1804 is the only one on the IGI for a John Clish in the relevant period. Which leaves two obvious scenarios: either, against the apparent odds, there were two separate John Clishes; or there was only one, and he kept the army equivalent of an RN man's "girl in every port". For the latter theory, the dates are certainly rather uncomfortable: they require him to have come north on leave to marry at the very time when a Sussex woman was already six months pregnant with his son-to-be William. We know that he had few claims to sainthood -- but even the practicalities seem rather challenging!
If anyone were prepared to pull out a little plastic card, the search engine has also served up a possible evidential "decider". By great good fortune a poor law settlement examination has survived in Ringmer parish chest for:
John Clish, private in the artillery drivers at Ringmer
Settlement examination 4 Oct 1811
PAR461/32/4/8
-- East Sussex [Lewes] Record Office, via A2A
The fact that John Clish, the 75 year old miner at Heworth in 1881, gave his place of birth as Woolwich is at the very least a major co-incidence, and if anything it does rather strengthen the case that JC the Convict was indeed the same man as JC the Ringmer RHA man. But the puzzle is far from unravelled.
Rol
Postscript: I see that other RootsChat users have already ploughed furrows in the RHA-Ringmer field -- per this thread (http://www.rootschat.com/forum/index.php?PHPSESSID=3h12i2hb8m630iqtifltjhs6l0&topic=215146.0), dating from 2007-08.