Hi Kevin,
I'm going to do a little more digging and see if I can find anything extra for you.
For all the peepers, the 1881 census:
Source Citation: Class RG11; Piece 3738; Folio 19; Page 32
32 Park Road Back, Parr, Lancashire
Head - James LEATHER - 70 (c. 1811) - Newton - Labourer
Son (head) - James LEATHER - 23 (c. 1858) - St. Helens - Miner
Wife - Ann LEATHER - 20 (c. 1861) - Widnes
Son - James LEATHER - 1 month (c. 1881) - St. Helens
From St. Peter's, Parr I've found the following two grave book records plus a MI mentioning a James LEATHER:
Grave Purchased by RICHARD LEATHER
JAMES LEATHER 5 September 1866 2 yrs
RICHARD LEATHER 21 November 1881 41 yrs
ALICE PARR 9 October 1922 81 yrs
JOSEPH LEATHER 10 March 1926 59 yrs
RICHARD and ALICE LEATHER
JAMES LEATHER
September aged 2 yrs 3 mnths
RICHARD LEATHER
19 November 1881 aged 41 yrs
ALICE PARR
Wife of WILLIAM PARR
9 October 1922 aged 81 yrs
JOSEPH LEATHER
Son of above
3 March 1926 aged 59 yrs
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Grave Purchased by Mr LEATHER
MARY E LEATHER 25 March 1889 3 yrs
THOMAS SARBUTTS 16 December 1891 64 yrs
MARY ELLEN LEATHER 21 September 1894 5 mnths
HENRY LEATHER 4 November 1895 6 yrs
ANN ELLEN LEATHER 23 March 1896 2 mnths
ESTHER ELLEN LEATHER 10 September 1901 12 mnths
ALICE MAUD LEATHER 18 September 1902 8 mnths
JAMES LEATHER 23 May 1933 76 yrs
SARAH ANN LEATHER 9 May 1939 78 yrs
The above grave purchased by Mr. LEATHER does not appear to have a headstone. The James LEATHER buried in this grave is about the right age to be the son of your James but it may just be a coincidence. The entry from the burial register for this burial may help or, of course, the death certificate.
I've also found the following burial at St. Peter's, Newton:
22/11/1836
James LEATHER, Newton, age 64
Could the above be a relation of your James born c. 1811?
That's all from me for now but if there is anything else I can look up for you please don't hesitate to ask.
Best Wishes, Kirsty :)