Thanks for all the amazing feedback everyone!
More images below. Status after having heating on continuous for 30mins
1) Its a pressure gauge not temp gauge showing just over 3 bar?
2) Engineer took off the white device - is that motorised mixing valve? He tried to depress the metal pin down with head of screwdriver even with significant force he struggled to depress the pin so he struggled to see how the white device would have the power to depress it - does that make sense?
3) The pipe work to the left of the ESBE device is red hot to the touch - everything to the right of ESBE device is somewhere between cold and luke warm - barely any heat at all in any of the pipes - including those entering the ground. Had heating on circa 10 hours - floor was warm after that time. All thermostats are set to 27 degrees + and room temp was nowhere near that.
4) Is the pump running, can you hear it or are there any lights on it?
No lights on it but I can hear it running I think
5) What is the temperature dial, the big white knob top left that says "upnor" set to?
It has no temperature on it. See comments on pics. Its looks like it some kind of on/off mechanism? Theres a red indicator inside it by the looks - should that be in down position?
6) What are the pipes embedded in, underneath the amtico?
Dont know. I am on ground floor. Theres multiple low rise blocks being serviced by central source circa 500 metres from me. Feedback from resident on non ground floor in another block is his takes 2 hours+ to get warm. Another guy in my block - not ground floor - where engineers just visited - reported same issues - of different design - have quoted him £250 parts and £250 labour for fixes. Engineer admitted to me he is a generic electrician and not an underfloor expert. Can anyone recommend an underfloor expert in London area please?
7) Im awaiting photos from my neighbours in our block. It looks like our entire block is different make to other blocks. Im 8 years in to 10 years of NHBC warranty. Doubt they will do anything as its broadly "working"?