I hope this is your lucky day, because I happened to log on before I took a trip to the museum today. The Manx Museum has 3 voumes of KWC pupils.

The 1927 editiion, KING WILLIAMS COLLEGE REGISTERS 1833-1927 PAGE 450:

Entrances in may 1926:
CORKILL, Harold William, born July, 30th, 1912.Son of W. H. Corkill, Bank House, Laxey, IOM Walters (House)

From the next edition (sorry, forgot to note edition date)

Page 719
CORKILL, Harold William born 30th July, 1912 House Walters Left July 1931
S. of W. H. Corkill, Laxey
Prae. C.S.M. in O.T.C. shooting VIII
Liverpool Univ. 1931-36. Dep Architecture
A.R.I.B.A. 1936
Univ. Cert. in town Planning and Civil Design 1937
Chartered Architect
Served in R.A. 1939 - 46 (Major) R.A. (T.A.) 1951-55 (Major)
President Liverpool O.K.W. Socy. 1953-54
Died at Caldy, Cheshire, 5th Apr. 1955

I hope this gives you plenty of leads to follow. I didn't have time to look up other Corkills of the era, to see if he had siblings at College. Why don't you get in touch with K.W.C. and see if they can give you further information. They must surely have a website. They have an old boys magazine called the Barrovian, which contains obituaries, etc. Wish you well.

Page 719
CORKILL, Harold William (born) 30th July, 1912 (House) W (walters)
left July, 1931
s. of W. H. Corkill, Laxey
Prae. C.S.M. in O.T.C. Shooting VIII
Liverpool Univ. 1931-36. Dep Architecture
A.R.I.B.A. 1936
Univ. Cert. in Town Planning and Civil Design 197
Chartered Architect
Served in R.A. 1939 - 46 (Major). R.A. (T.A.) 1951-55 (Major)
President Liverpool O.K.W. SOCY. 1953-54
Died at Caldy, Cheshire, 5th Apr. 1955.