I thought it was all built in 1970s but then I spotted a Hansard (house of commons transcript) dated 1966 that talking about the A41 says:-
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"Apart from the New Ferry bypass, which is dual-carriageway at the northern end, it is throughout its length a single carriageway four-lane road"
Here is a picture from about 1972 showing the junction at Sefton Road/Stanley Road area - this accounts for the silly road layout on the East Side of the New Chester Road around there now.
In a time of universal deceit - telling the truth is a revolutionary act. George Orwell
When the debate is lost, slander becomes the tool of the loser. Socrates