Hi -
I had a look through the 1851 and 1861 census indexes for John Leabrook, but there was nothing like it.
However, a bit of lateral thinking suggested that maybe, if he had a Jersey name, it might be difficult for the English census enumerator in 1871. So I looked up John Le Brocq (It sounds just like 'Leabrook' with a Jersey accent). It's quite a common name in Jersey, and I have looked in the parish of St Brelade, which is where the town of St Aubin it located.
There are five John Le Brocq's, in the age range, named in 1851 - but only one born in St Brelade (St Aubin) with a father called John:
LE BROCQ
John Head 36 shoemaker Jersey St Peter
Nancy 38 wife Jersey St Martin
Edward 13 son scholar St Peter
Charlotte 9 daug " St Ouen
Mary Ann 7 daug " "
Harriet M 5 daug " "
Esther 3 daug " "
John 1 son St Brelade
This would make John jnr born circa 1850 - is that likely? Do any of the family names fit with other information?
In 1861 I think I have the same family -
LE BROCQ
John Head 46 Farmer St Brelade (?)
Ann [is Nancy a corruption of Ann?] 48 St Martin
John son 11 St Brelade
Louiza [sic] 5 St Martin
Eliza 3 St Brelade
Of course this could all be barking up the wrong family tree - but does any of it sound feasible?
Mike E