Thank you for your prompt service Barbara! I've copied the list onto a document I can keep for future reference.
I've looked up the birth records on the Tees Valley website and it gives me MJ codes for all of them. The next part of the code for one of them is 071, your list shows 71 as Southfield Road Methodist, so perhaps it could be there. I know that the family lived around the Linthorpe area at the time, they were Wesleyan Methodists so that does fit in the Non Conformist bracket, maybe they were different for baptisms as well. I'll try the Register Office and see what they have to say. Thanks for your help.
P.S. Don't suppose you know what SN and SW are for Stockton? (Pushing my luck here!

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