I do have the 1928 Certificate but I know all the information on it is not true.
Charles Pearce is listed as a pedlar and as deceased.
Witnessed by a L.Pearce and a M. Deller
Address for both the bride and groom is listed as 42 Campbell Road, Islington. I believe this is a lie.
Thank you for providing the marriage details
edit to add
Did John & Elizabeth sign their names?
I wonder what the christian name of witness
L Pearce is and how they are related to John

That's interesting as
Josiah & Lily Pearceaddress
32 Campbell Road, Islington on their 1922 marriage certificate

and his father Charles is also noted as deceased but no occupation given

Looked at the
London Electoral Register for the above address
42 Campbell Road Year
1938 there's
Joseph & Lily Pearce and living at number
32 Campbell Street persons with surnames Clark & Moss (not checked to see if the persons named Moss are related to Lily)
surnames Moss & Clark
Electoral Date
1939Street Address
32 Whadcoat StreetWard or Division/Constituency Islington North and South
County or Borough Islington
and at number
42 Whadcoat Street is
Joseph & Lily Pearce
I think you need to look at the 1939 register entry. Use daughter Minnie b 1935 to search. Look at the entry for John - his name & in particular the entry for his birthdate
We are not allowed to post those details on RC
Yeah, I have that entry but there are 2 birthdates listed.
Don’t now if there might be a connection or just a coincidence to this Pearce family in 1921
Belvedere, Erith, Kent - not found them in 1911
Charles Pearce 1885 -
Ann Pearce 1885 -
Rally Pearce 1906 Belvedere, Kent
Henry Pearce 1913 Belvedere, Kent
George Pearce 1914 Belvedere, Kent
Can't post further details other than what's freely available - you have to pay to view the original census for further details - I think/hope I'm ok in saying that the street address is similar to John Pearce's in 1939