Anisty Castings do 70's football hooligans in the Agro miniatures range. Some of the Offensive Miniatures rioters and Foundry Street Violence (skin heads and punks) might also be suitable? A lot of the Crooked Dice figures are also from around the right time period.
Ainsty's Aggro range looks to be by the same sculptor as Geezers (Martin Baker?), so those should fit well.
The Black Tree Doctor Who range will yield a few civilians in appropriate fashions, but like Crooked Dice and Copplestone, they are on tabs.
Artizan has the other half of the Kiss Kiss Bang Bang range, and a lot of the Thrilling Tales figures would work too - lots of people in the 1970s still dressed much the same as at mid-century, especially older folk. So quite a few WW2 and Inter War ranges will have usable figures. Check out the Civilian packs from Musketeer in particular for workmen in flat caps, housewives in pinafores, a vicar in tweed and a schoolboy in shorts and cap (just like I was wearing at the start of the decade!).