Thanks for those links, unfortunately I didn't turn up anything new with them.
I've done a bit of investigating since the previous post and have discovered a few things:
William Wilkinson Brown emigrated to Sydney and settled in Berala where he married Elizabeth Florence Surname(?) and worked as a railwayman. Though I'd previously mentioned that he initially stayed with a Wilkinson, I've since found out that was NOT true, rather, my grandfather (his half-brother) stayed with him when he went to NSW, before moving on to live in Tamworth with my great grandparents George Thomas Byrne and Annie Mary Byrne nee Reilly.
Marriage 1: Jane Thompson Wilkinson m. Samuel Brown (from Monaghan)
Children: Samuel James Brown (b:1892) and William Wilkinson Brown (b: 1893)
Marriage 2: Jane Thompson Brown m. Charles Leek (1901)
Child: James Stewart Leeke (1904)
Jane Thompson Wilkinson's first husband was Samuel Brown(e?) of Monaghan. The Wilkinsons in general used the traditional naming pattern. Their second child William was named after the maternal grandfather so Samuel was probably the paternal grandfather's name. Having checked the Griffith's Valuation I found quite a few SAM BROWNEs and one spelt BROWN. The family now spell it with an "E", and records seem to vary.
As their first son Samuel James was born where his father was stationed at the time in Co. Wicklow, and William in Aghadowey, this has caused me to wonder if, when their father died so prematurely of which cause I don't yet know, he was buried at Aghadowey or in Monaghan. I haven't found a graveyard record at Aghadowey Presbyterian which denomination I am certain they were. Samuel James married an Anglican Mullaghinch neighbour called Rachel Doherty and they were buried with the Leekes at St Guire's.
As I mentioned, the wilkinsons not only used the traditional naming pattern, but also included surnames as middle names. This got me wondering as to whether Jane Thompson was the name of William the cooper/carpenter's wife. I've looked up a couple of genealogy sites (Emeraldancestry and derry.brsgenealogy) but alas to no avail!
Hugh Wilkinson was buried in Kilrea with wife Nancy Campbell - you'd wondered where he ended up, and the first website you sent me stated just that. Finally, there was no "Charles" from the Wilkinson/Brown marriage, they were grandchildren.