I do actually remember Summer Wine from this period, with Blamire as third man and with the library featuring heavily, but for a long time no one else seemed to remember anything prior to Foggy taking over.
That might be because it used to be shown at 8pm and, as can be seen from the pilot and several of these first few episodes, was a rather different proposition from what a lot of people think of when the show is mentioned.
This Summer Wine is NOT soft, bucolic and cuddly. These three men smoke, swear, read mucky magazines at the barber's (who also has a topless calendar on the wall which I notice Drama channel have blurred out) & have strong opinions about religion and politics. Of the two characters that went on for years, Compo & Clegg, the most obvious difference is in Clegg. He's not actually all that likeable and he's certainly not timid. He's not long widowed (Mrs C's gravestone in the pilot says she died 1971. It's now 1973) and though he seems to miss his wife in some ways, he also seems to relish his new freedom.
The other feature of these early episodes is that they feel much more theatrical. At times the actors seem to be declaiming, as though in order to be heard by an audience some distance away.
It's entertaining enough, especially if you do remember the 70s (everything seems authentically grimy and run down) but in some ways it now seems amazing it lasted so long as it feels like a show that wouldn't have appealed so widely.