Hi Julian When you mentioned the McSweeney and Donaghue link, do you mean the marriage of Peter McSweeney (B. 1827, Cork, Stonemason and Cooper) to Mary Donaghue (B.1827), in 1846 (not 1866??) in Cork?
The only reason I ask, is that Peter is my great, great, great granfather, and his son, John McSweeney (B.1855, d.06/07/1927, Publican), is I believe, somehow related to Terence MacSwiney (d.25/10/1920). (Although to date, I've not had much luck in ironing out this association - probably second cousins or even further afield).
Consequently, John had a son (another John, B.05/07/1908, d.10/11/1926), who came over to London, married Rosina Mary Shore (widowed, formerly Neale), and also became an publican. They owned and managed the Shipwright's Arms,and then the Royal Oak pub, Union Road, Rotheride. My grandfather Neil,(John's son), recalled (beofre his death)the MacSwiney family staying with the McSweeney's fleetingly prior to Oct 1920, but his father never explained the exact family relationships.