Also, marriage was 1944, did you mean to say 1945 for divorce to first wife?
For some reason, I am not finding the divorce indexed on the NRS website, which I thought it would be as they say:
From 1935 to 1984, individual divorce cases are listed in our catalogue and can be found by searching for either party involved in the action.
And, neither the 1919 and 1944 marriages, nor the 1966 death, are indexed with a middle name for Richard.
In 1892, not 1893, there is this birth:
GRAY
RICHARD CRADDOC
CRADDOCK
M
1892
578 / 686
AYR
So if your chap, it certainly looks like he rarely used 'Craddock' or even 'C', on records in later life.
I think I was lucky and found the record before it was pulled from the site. Originally, it should have been released in 2020, but when the law was changed it got pushed to 2045.
And you are correct, he often does not use that middle name, but I do have birth, marriage (x 2), divorce, and death records.