Walton Bell, of Yorkshire: when this Walton was baptised on 11 Oct 1841, his father John was a Sargeant in the 1st Royal Dragoons, and they were living in Barracks. They give a birth date of 17 sept 1841.
I cannot find him in the GRO. It is entirely possibly that he (John) was stationed in Quebec, and shipped back when Walton was born. IF the ship was very very VERY fast! If I remember correctly, I did check the British born overseas series, and had no luck.
As to the John Yates problem, in my opinion, if you reject the newpaper notice in Reply# 13, you have to reject the marriage newpaper item in Reply #12. I have looked through all the John Yates military records, and in the right regiment in the right time period, there was only on that was a clerk and a staff sargeant. All the rest were wrong regiments, and Privates. There were two I spent a long time on, as one was in the 6th, but he was a private, and never rose above that. The other one, also a private, died before the one in question. None of the others came close. Somewhere in here, Daisypetal posted the movements of the 6th regiment, and they were spot on to match the newpaper items and timing of their marriage.
No one likes a brick wall. It seems the marriage of Mary and John never got off the ground; perhaps she didn't want to move to Aldershot. That part you will never know. And it drives me nuts she is never with her parents in the early censuses!