Following extensive ONLINE research, and considerable untangling of all the many individuals of the same names who lived at that time, a summary of the principal data found for these "Band of Seven Brothers" (the first 4 being as yet unknown) is as follows:-
(5) Capt. Colin Campbell, Royal Navy (c.1776-1842), retired RN 1814, lived at Brunswick House, Gloucester,
married (1st) 1802 (London), Amelia PATERSON (1783-1808), dau. of Daniel PATERSON (London), had an only child,
Capt. John Campbell, HEICS (1804-1884), married 1831, Jane Smith STONE (1796-1885), no
issue;
married (2nd) 1823 (Walcot, Somerset), Elmira PAGE (c.1774-1843), widow of Lt.-Gen. Richard GORE, no issue.
(6) Lt.-Col. John Campbell, 55th Regt., (c.1780-1832), half-pay 1818, lived at Belgar, Jamaica (coffee plantation),
married 1808 (Exeter), Anne ROWLAND, dau. of Edward ROWLAND (Liverpool), had issue (who all lived and died in Jamaica),
1.- John Charles Campbell (1809-1854), married Louisa Samuels (surname unknown))
2.- Edward Colin Campbell (1813- ?)
(7) Capt. Robert Campbell, 9th N.I., HEICS (c.1782-1820), Barrack-master at Surat, India,
married 1819 (Edinburgh), Jane CAMPBELL (c.1793-1852 at Saughton Hall Mental Asylum, Edinburgh) *SEE NOTE BELOW*, dau. of Archibald CAMPBELL, writer (Edinburgh) [see "The Scots Peerage", Campbell of Breadalbane], had an only child,
Archibald (1820-1820), died infant in Bombay
NOTE :- There is an important error in "Records of clan Campbell in the military service of the honourable East India Company 1600-1858", which has been subsequently repeated in many pedigrees online, indicating that Jane Campbell married Capt. Robert Campbell (died 1840) of Ardchattan; this has now been proved to be INCORRECT (see proofs in the family tree mentioned below).
The complete family tree (named CAMPBELL) of the above, with all the proofs attached, can be found on Ancestry – when researching the "Profile" for an individual, please click on "GALLERY" to find all the items of evidence, and in particular download the WORD file named for that individual, in which will be found many screenshots from online sources that considerably expand our knowledge of their lives (e.g. there is a fascinating eyewitness account of Capt. Robert in a field hospital at Bergen op Zoom in 1814 after being wounded by grapeshot).
Frustratingly, apart from the fact that the England Census 1841 indicates that Capt. Colin was born in Scotland, and that Capt. Robert was married in Scotland, no link has yet been found to any family there. Some clue to their origins might be found by deeper research into their individual service records. If anyone can provide any further details of the family of these "Magnificent Seven", do please post here.