There's a possible newspaper reference to your father in 1935, although it could be one of other Stephen Corner's.
I've included a few other possible newspaper items for the family.
Newcastle Journal
29 May 1928
Durham Horse Parade
page 2
...
Special prizes given by Major H Peele for best pit ponies in the show: - Lambton, Hetton and Joicey Collieries, Hetton (M. Corner), Weardale Steel, Coal, and Coke Co., Ltd, Thornley Colliery (C. Cook)
Sunderland Daily Echo and Shipping Gazette
22 Jul 1929
page 2
Hordon Cottage Hospital
Carnival & Horse Show
...
The Douglas Murray Challenge Cup for best pit pony in the show, 13 h h or under, was won by Mr M Corner (Hetton Lyons Colliery).
Sunderland Daily Echo and Shipping Gazette
11 Jan 1934
page 4
Hetton Man Hurt
Caught by a fall of coal while working on the mine at Hetton Lyons Colliery last night, Joseph Corner (29), of Richard Street, Hetton, received injuries to the head and ribs. He was removed to Sunderland Royal Infirmary and detained.
Sunderland Daily Echo and Shipping Gazette
17 May 1934
page 6
First-Aid Successes
Hetton-le-Hole St John Ambulance Brigade, in an endeavour to further first-aid, promotes a First Aid and Cadet Student's Class. The class was recently examined by Dr J A Hall, of Fence Houses, and the results of the examination are as follows:
Certificates: ..., S. Corner
...
Sunderland Daily Echo and Shipping Gazette
10 Jun 1935
page 8
Hetton Inquest
A verdict of "Suicide while of unsound mind," was returned by the Coroner T V Devey at an inquest on Saturday night on Mary Ann Slater (58), of Lyons Colliery, Hetton, who was found hanging in an out-house on Thursday night.
Evidence given by Mr Slater showed that his wife had been in ill-health recently, and was depressed.
Stephen Corner, who found the woman's body hanging, and immediately applied artificial respiration until the arrival of a doctor, was complimented on his sensible action.
Sunderland Daily Echo and Shipping Gazette
02 Aug 1937
page 2
Value Of Air-Raid Precaution Work
Collieries Official's View at Hetton
Ambulance Garden Party
Value of air-raid precaution training was stressed at Hetton Ambulance Brigade Garden Party, in the grounds of the Hetton House, Hetton, on Saturday afternoon, by Mr P S Blunden, Safety Inspector to Lambton, Hetton, & Joicey Collieries Limited, and County Officer and Air-Raid Precautions Officer of Durham County District of St John's Ambulance Brigade.
Mr Blunden said he was pleased to see by the certificates which had been presented the Hetton Ambulance Brigade was giving a lead in air-raise precaution work.
...
Nursing Display
...
Medallions: - Messrs M. Corner, S. Corner, M. Summers, and R. Hope
...
Sunderland Daily Echo and Shipping Gazette
14 Aug 1939
page 5
Hetton Carnival
Parade, Jazz Bands, and Fancy Costumes
...
Cleanest pit pony, - M Corner, Hetton Lyons Colliery