The original poster didn't ask for this information, possibly because it's already known or not relevant, but I can't resist:
1911 census: Malcom Leon Cowin s/o George Frederick John Cowin & Maud Marion
42 Norbury Crect, Melfort Rd, Norbury SW RG14/3353 ed31 sch106
George Frederick John Cowin - head - 33 - mar - Insurance Clerk, worker - born Clapham Junct.
Maud Marion Cowin - 30 - mar 8 yrs - 2 ch both still living - b. Surrey, Croydon
Malcolm Leon Cowin - son - single - 4 - b. Surrey, Norbury
Maud Mary Moss - servt - 16 - single - General servant, domestic b. Custom House E
4 persons/7 rooms
Freebmd Marriages (Ancestry)
George Frederick J. Cowin Jun-Aug-Sep 1902 Croydon, Surrey vol2a p565
Maud Marion Gillemand
"Two children born alive, two living" - where is the other one?
Freebmd births (Ancestry) searching 1901-1911:
1904 A-M-J George Alexander Cowin Croydon, Surrey
1911 J-F-M Shiela G Cowin (with diff. parents 1911)
1911 census George Alexander Cowin
70 Gleneagles Rd, Streatham, London SW RG14/2318 ed33 sch103
William Thomas Dolamore- h - 35 - mar - Insurance Broker, own a/c - Surrey, Croydon
Mary Beatrice Dolamore - w - 26 - mar 3yrs - 1 child, living - Surrey,, Croydon
Mary Jane Dolamore - mother - 70 - widow - Middlesex, Westminster
Donald William Gillemand Dolamore - son - 2 - Thornton Heath (?)
George Alexander Cowin - nephew - 7 - Surrey, Norbury
Catherine Jne Harris - servt - 19 - s - Gen. servt. domestic - Kent, Folkestone
6 persons/ 10 rooms
Freebmd Marriages (Ancestry):
William Thomas Dolamore J-A-S 1907 Croydon, Surrey v.2a p.565
Mary Beatrice Gillemand
1901 census Mother & aunt of Malcolm Leon Cowin:
8 Lodge Rd, Croydon, Surrey RG13/643 f.121 p37 sch230
Sarah A Gillemand h wid 53 Living on own means. Sussex, Brighton
Annie G Gillemand d s 23. Worcester
Shand* Marion Gillemand d s 20 Draper's assistant. Surrey, Croydon
Mary B Gillemand d s 16 Draper's apprentice. Surrey, Croydon
Sarah H Fabian mother widow 74 . Sussex, Brighton
(*seems to be enumerator's misreading of 'Maud')
1901 census Malcolm Leon Cowin's father:
10 Decimus Burton Rd, Croydon RG13/646 f.46 p.20 sch120
John Cowin h m 54 Draper's traveller. Kent, Lydd
Annie I/J Cowin w m 53. London, Belgravia
Flora E Cowin d s 26 Governess, school. Kent, Ashford
George J Cowin s s 23 Clerk commercial. London Clapham Junction
Ernest M. s s 12. Surrey, Croydon
There are obviously quite a few leads here to getting back further - and I have got two more generations of Dolamores in 1901 - but I probably shouldn't get too diverted here as I suspect no-one really wants to know!
If there is an IOM link to the name Cowin it seems to be before 1847. 'Spose I might find myself looking into that a bit more...