Yes it does have this valve. Another symptom I have remembered is that occasionally the temp light would flash signifying low coolant (coolant is fine) or overheating which it's not. It will flash from first ignition till i get there without turning off but often if I switch it on and off it will go off and stay off. I had considered an air lock also so will try to flush that out now.
First I would bin those valves. 22mm copper pipe to delete these.
Next you need to fit a blue coolant cap if you haven't got this already and be sure that the O ring is fitted to the cap.
Had this on many mk2's where the black cap would not release pressure and cause pipes to blow/ weak corroded core plugs to leak.
Take the radiator out and give it a good inspection. A small weep is enough to cause this exact problem
Bleed the system and add a very strong mix of coolant.
When bleeding mk2's I always disconnect the water flow exit pipe from the matrix and wait for a nice flow of water to come out. Then connect the pipe and do the same with the radiator. Speeds things up.
