Hi Elizabeth
Just read your post.
I found my father's Mechant Navy record for the 1950s in the UK's National Archives online Discovery catalogue. You can order a copy on line. They will first give you an estimate of the copying cost and you then have several options for delivery. Mine cost GBP 5.80.
I don't recall off the top of my head whether he was under his full name or just first initial and surname. The record also listed his date of birth and where he came from so it was easy to determine it was him.
The website is:
www.nationalarchives.gov.ukthen go to the Discovery search page.
They take up to 14 working days to process the request after payment has been made. (I'm still waiting for mine to arrive.)
Hope this is helpful even though it is so long after your original post.
Therese