An uncommon surname, moreso in Lincs.
Apart from those already given, all I can find in Lincs
Q3 1934
George INSLEY
N Kesteven 7a 422 age 75 (the area south of Lincoln - see
http://www.ukbmd.org.uk/genuki/reg/districts/north%20kesteven.htmlSeptember 1935
Caroline B INSLEY
Grimsby 7a 618 age 52
Also 1938 Scunthorpe, Sylvia aged 13
Possible marriage
Marriages Jun 1904
Insley George William Grimsby 7a 1595
James Joseph Grimsby 7a 1595
Mason Emma Grimsby 7a 1595
Oates Caroline Beatrice Grimsby 7a 1595
I would have thought this chap was somehow involved
Births Dec 1881
Insley George William Caistor 7a 619
He seems to have been the son of the chap born in Birmingham in 1855. I note that George from Birmingham appears on 1881-1901 censuses at least two years younger than he should have been (23, 33, 42).
I have checked 1920-41 ... only 2 quarters were missing for that period.