Help on thermostat replacement

I’ve just spent the day removing and replacing the thermostat on my Audi A6 1.9TDI-PD. The job went really smoothly. I used all genuine VAG parts including a new pipe thing that goes on the thermostat. Then filled it up with 50:50 G12 ++ and de-ionized water.
The car has taken just under 5ltrs, I only removed the bottom pipe on the radiator to drain the coolant so I’m not sure much or any more came out. (BTW I did turn the new thermostat 90 degrees in the pipe to secure it)
Anyway I started the car and held the revs at 2000rpm for about 5mins maybe a bit more. The gauge went to about halfway between normal temp and cold, the oil temp went to about 60-70C. I turned off the car at this point because I didn’t feel something was right. All the rad pipes are cold, the heater is working but the little water pipe going into the top of the expansion tank is not squirting water when the car is running. When I squeeze the top pipe it does squirt.
I’m worried there is no water in the block as the temp gauge read higher after being turned off then it cooled down very quickly. Would the car get up to temp properly just revving idling. I’m worried if I take it out it will overheat.
Any help would be great
Will

5 mins probably isn't enough for your thermostat to open, so I would let it idle a bit longer. You can also, while the car isn't moving, and there isn't any pressure in the system, take the reservoir cap off. You should see bubbles. You'll be able to top it off as needed, but be aware that some coolant will leak onto the ground (so don't park near your wife's favoirte persian rug!)

I have been running the car with the cap off and the bubbles lowered the level of coolant, so I kept topping it up to max. now this has stopped.

My worry is that none of the pipes got at all warm even when the gauge was registering about 70C. I know there is coolant in the top hose because I can hear it move when I squeeze the pipes.
If there is water in the top hose does that mean there is water in the block. Or could there be a massive air pocket in there.
The only pipes to get hot were the heater pipes. Also I think it was longer than 5minutes at 2000rpm then I idled it for about 5-10minutes. The head and block felt very hot and the oil sump did feel hot as well, still cold pipes.

took the car out today and it was perfect. Finally the temp gauge shows 90C and points straight up when hot. Also I noticed the oil temp was about 90-100C where as it used to fluctuate just below 80C.

I have noticed there may be a small leak from the lower rad hose. Its a weird design having a clip to keep it in place rather than the spring clips most VAG cars use. The pipe on the Audi has a little oring in it which I didnt replace however looking on ETKA shows it is a non replaceable part. And the workshop manual on ELSA says nothing about replacing anything. So i'm just going to keep my fingers crossed in the hope it was just residual coolant from draining.

Will