2004 Jimny M13A High Temp after recon head and head gasket replace

I've just recently replaced head gasket and recon head on my new to me 2004 Jimny M13A.
After re-nstalling everything I have done several short trips near home of approx 8 km with temp sitting in middle.
I live in a remote rural location about 30 minutes from nearest town, today did a run into town.
After about 20km sitting on approx 80-90km/h the temp gauge starting rising to the level in pic.
I turned on heater lever and temp starting dropping so did my speed as I entered town limits.
On returning home temp approx middle of gauge and after about 20 minutes starting rising again, turn heater again temp drop slighty.
Temp never went over the level depicted in pic. 
Have I missed something.
Didn't look at Thermostat or replace radiator.
Radiator look OK although didn't test other than flushing with hose.
Any guidance please.
TIA
Kappy 

Seems like you have an air lock somewhere, I would bleed it again

The coolant systems on these does take a bit of time to bleed up. Run it from cold with the radiator cap off until the thermostat opens and keep topping it up. Squeezing the top radiator hose helps to burp a bit of air out.

I'll try that again before I remove the thermostat.
I don't recall the thermostat opening after topping up.
Maybe need to be a little more patient.
Does it take a bit for it to open?

Yes it takes a while. You can feel the warm water circulating the rad when it opens.

Ran at idle/fast idle for 20 minutes, didn't any evidence of thermostat opening.
Feel thermostat maybe faulty, possibly responsible for earlier over heating issue.
Will remove when called down.
Worthy of note, I was unable to get 5 litres of coolant in system, borderline 4 litres.
More to be revealed.
Thanks
Kappy