hi i went quickly to Griffiths valuation and just taking these three results for their civil parish location moved back 30 + years see below
Lennon Patrick Drummiller Aghaderg Down dated 1863
Lennon Patrick Corbally Down Down dated 1863
Lennon Patrick Village of Magheralin,Ballymakeonan Magheralin Down 1864
I looked up the tithes applotment for all three parishes
Aghaderg civil parish
http://www.irishgenealogyhub.com/down/tithe-applotment-books/aghaderg-parish.php#.VgWrKkvU4YU Lennon, A. Townland: Drumsallagh Year: 1828
Lennon, Bern. Townland: Drummiller Year: 1828
Lennon, Bernd. Townland: Drummiller Year: 1828
Lennon, Bernd. Townland: Lisnagade Year: 1828
Lennon, Edward Townland: Lisnagade Year: 1828
Lennon, James Townland: Drumsallagh Year: 1828
Lennon, Michael Townland: Drummiller Year: 1828
Lennon, Patrick Townland: Drummiller Year: 1828
Lennon, Richard Townland: Lisnagade Year: 1828
Lennon, Widow Townland: Drummiller Year: 1828
Lennon, Widow Townland: Lisnagade Year: 1828
Down civil parish
http://www.irishgenealogyhub.com/down/tithe-applotment-books/down-parish.php#.VgWssUvU4YULennon, Edward Townland: Magheralegin Year: 1833
Lennon, John Townland: Woodgrange Year: 1833
Lennon, Joseph Townland: Corbally Year: 1833
Lennon, Mary Townland: Corbally Year: 1833
Lennon, Nichs. Townland: Corbally Year: 1833
Lennon, Peter Townland: Ballystrew Year: 1833
Lennon, Thomas Townland: Hollymount Year: 1833
Lennon, Wm. Townland: Ballymote Year: 1833
Lennon, Wm. Townland: Ballystrew Year: 1833
Lenon, Jno. Townland: Hollymount Year: 1833
Lenon, Peter Townland: Quartercormick Year: 1833
Lenon, Thos. Townland: Hollymount Year: 1833
Magheralin civil parish
http://www.irishgenealogyhub.com/down/tithe-applotment-books/magheralin-parish.php#.VgWtokvU4YUno Lennon found
So one could search every Tab for every civil parish and many may be missing.
However the one found Patrick living in 1828 in Drummiller in Aghaderg
Church records exist see
http://freepages.genealogy.rootsweb.ancestry.com/~rosdavies/CHURCHES/A-I.htm#AghadergAGHADERG, CO. DOWN
C.I. Aghaderg (Dromore diocese)
Baptisms,1814-70; marriages, 1814-49; burials, 1814-
1980; vestry minutes, 1747-1841. MIC583/9; CR1/47
C.I. Scarva (Dromore diocese)
[Earliest registers destroyed in Dublin]
Baptisms, 1877-; marriages, 1851-; burials, 1850-;
vestry minutes, 1850-. In local custody
P. Glascar
Baptisms, 1780-1844 and 1885-1931; marriages, 1781-
98 and 1822-32, with indexes, and 1845-1903;
communicants’ roll, 1890-1940.
Session minutes, 1760-1818.
MIC1P/63
In Presbyterian Historical
Society
P. Loughbrickland
Baptisms, 1842-1903; marriages, 1842-89; committee
minutes, 1842-1905, with accounts up to 1912; stipend
payers’ book, 1862-83; communicants’ roll, 1882-91. MIC1P/181
P. Scarva
Baptisms, 1807-1964; marriages, 1814-1936; lists of
new communicants, 1858-94 and 1924-7;
communicants’ roll, 1927-9 MIC1P/182; CR3/53
Guide to Church Records
58
Public Record Office of Northern Ireland
Crown Copyright 2010
Ref. No.
R.C. Aghaderg (Dromore diocese)
Baptisms, 1816-76; marriages, 1816-76; burials, 1838-
75.
MIC1D/29
My quick assimilation of that means the births from say 1816 exist with a chance of earlier ones.
Many family quests don’t have this collection of records available. So back to yourselves BUT I would be thinking someone has done John Lennon family history in greater detail than you have found so far but who and where is it. examples might be
SOG Society of genealogists, unchecked
The Guild of One Name studies Hasn’t Lennon registered.
http://www.nifhs.org/results.htm has lennon entries but not an obvious connection
Another source might be in indexs that list the father of children eg
http://www.ancestryireland.com however that’s too early or too late for identifying where James was born
JAMES LENNON 1816 father PATRICK Down
PATRICK LENNON 1857 father PATRICK Down
THOMAS LENNON 1855 father PATRICK Down
JAMES LENNON 1857 father PATRICK Down
JANE LENNON 1858 father PATRICK Down
EDWARD LENNON 1858 father PATRICK Down
JAMES LENNON 1858 father PATRICK Down
PATRICK LENNON 1859 father PATRICK Down
HANNAH LENNON 1861 father PATRICK Down
I haven’t searched familysearch.org and after that I would be back to church records, but first seeing Ros davies versions rather than PRONI as she often lists other groups that have copies eg NIFHS and Familysearch etc Good luck anyway
BallyaltikilliganG