I would personally pull the clutch and renew the whole lot. But if you prefer not the I think people like demon tweets do cable kits so you can add in an adjuster.

You can probably drill out a bolt or buy a hollow bolt and put that through the bell housing where the cable goes through and then wind the bolt out to give you pedal adjustment. It looks like m10 or m12 would go through and the put the cable through that.

It looks like you clutch release arm has a crack in it...I would mig weld that up whilst at it.

Did the cortina maybe have a ratchet on the clutch arm...I think the Cossies may have had that?