Puzzling over a wedding photo

On 12 February I wrote in my blip about my great uncle Edward Cecil, who served on HMS Grafton in World War I. In 1921 Edward Cecil married Louisa. This is their wedding photo. The more you study it, the more tantalising it becomes.
 
You would think the couple sitting to Louisa’s left are probably her parents. If so, you might expect that the couple to Edward Cecil’s right are his parents. But they look too young. In 1921 Edward Cecil’s father was about 55. There’s certainly a family resemblance, but I would think this is more likely to be Edward Cecil’s brother than his father.
 
I do have a confirmed photo (extra) of Edward Cecil’s father, taken about 1928. It shows Edward Cecil holding his baby son and behind him his father, his nephew (just embarking on a naval career) and his eldest brother. I really doubt if his father is the younger man in the wedding photo.

Edward Cecil had four brothers and one sister. He was the youngest. Are they in the photo? I can’t see many family resemblances. One of the brothers was my grandfather, and I’m pretty sure he isn’t there.

Come to think of it, there don’t seem to be many older folk in this photo. Isn’t it a rather remarkably young wedding group?
 
So if Edward Cecil’s parents, or indeed his older relations, were not at his wedding, I wonder why not? I wonder how many of his siblings didn’t come to his wedding, and why not? And I wonder whether, after living through the War, Edward Cecil influenced his nephew’s choice of a career in the Navy?
 
I wish someone had recorded the names on the wedding photo. But even if they had, it probably wouldn’t answer the most interesting questions.