On ancestry, I've found the following:
on the 1891 census there's a George D B King living in Steyning with his (maternal) grandparents (when you look at the original the B looks more like an R, birth place and dates are correct).
George married a Mabel Bristow Q1 1900, in Thakeham in Sussex (she was born in Wiston Q1 1876, the same time as George). Thakeham is around 10 miles from Haywards Heath, close to Wiston.
In the 1901 census they are living in Steyning with their 3-week-old daughter Kathleen (Kinalda) King, with George presumably an assistant in his grandfather's grocer's shop.
Getting copies of his marriage certificate would confirm his wife's name, and maybe someone remembers a great aunt Kathleen. Her birth certificate might give some more info.
Kathleen married a Mr. Page in Steyning in Q1 1923. Her marriage certificate would tell you if George was still alive then.
Four people on genes reunited have a Kathleen King b. 1901 in Steyning in their family trees; I'm sure one of them would know more.
George King is too common a name for me to find a death record, although you may have more time. He isn't recorded in the Commonwealth War Graves website, so he probably survived the Great War. You could search for when and where Mabel died. I'd contact these nice people at the Steyning museum, who have transcrips of the parish records (although be aware that George's granfather was a Weslyan preacher as well as a grocer):
Chris Tod, the Museum Curator
Telephone: 01903 813333
Email:
contact@steyningmuseum.org.uk .
I think you'd find the answers there. Hope this helps.