Hi Mike
Not a lot to add on the marriage but bear with me on this....
John Armitage Bachelor married Sarah Shackle Spinster at St Mary's Ealing, 19th August 1827. He signed his name, she left her mark.
Their witnesses were Sarah Langston (x) her mark and Chas Atlee. His signature is all over the register, must have been the 'professional' witness.
Then I took a chance on the filmed baptism registers, but I was running short of time and the first one I looked at had the following
1803 Aug 21 Thomas Shackell s of Robert and Charlotte born July 31
1805 Dec 1 Sarah Shackle d of Robert dec'd and Charlotte born Nov 12
The burial register for late 1805 showed nothing for Robert so I don't know where is is buried at the moment.
I also didn't get the chance to look at earlier registers to see if there were any other possible siblings.
So now there's a dilemma...
The LMA is closing next week until January for a refurb so I can't look again for you until after Christmas and the Central library in Ealing where records are also kept is still shut for a major refurb which is seriously behind schedule because of very large cracks in the walls.
So I'm sorry if I have tantalised you with some information but not enough

Dawn