If Dobson is right, then we've clarified the matter as far as the situation up to the c18 is concerned. But what about the c19 and (early?) c20? My query was stimulated by a comment made by the 7th Earl of Onslow in an interview with Melvyn Bragg for the BBC series Routes of English:
What I’d call it is a perfectly natural accent because that was the accent I was brought up with. It’s different slightly to my parents and it’s different to my grandparents. I mean, the only thing I can remember is instead of saying "weekend" they would always say: “come from a Saturday to Monday”. They never used the word “weekend”; it was considered rather awful. My parents would definitely say "larndry", "larnch", "harnch", "Cumton", "Cuventry", "Brumton", lengthen sounds in "orff" and "gorn" and shorten them like "gel". Now I say some of those but not as many as I can sometimes try to remember to if I try to be very snobbish.
Here's the list of words again to which I've added 'haulm':
Addendum: There's a post by Jack Windsor Lewis in his Phonetiblog #321 (= 'Words Like Launch') of Christmas Eve 2010. In this blog entry he gives some additional information on the topic.