Thank you again for all your time. Please then suggest a stroller for us, lightweight, small fold, roomy, quality fabrics, good ventilation, suspension, lie flat and good for most terrain to fit up to 4 years. I wish, right!!! The Ergobaby Metro + and Joolz Air seem to be lacking. If you could suggest 2 or 3 I can research more and see which is available in Europe that would be great. I already have a Nuna and a Joie Chrome, both excellent but bulky and heavy so we end up not taking them out with us and definitely not for holidays or travel since they take up the whole boot of the car.
My best advice here, with some compromises (you cannot have all in one strilller I'm afraid) would be the Baby Jogger City Mini GT2. I mean, the ventilation itself is not above average, but the open seat and the fabrics will work ok and there is a large ventilation mesh in the canopy. The wheels and terrain capabilities are great and the seat is SO roomy, it will last. The stroller foilds VERY flat but is not the size of the cabin-sized models you mentioned, it is a bit larger pushchair.
Next, I will mention the Valco Trend which is a similar sized, even roomier in a way, has a mesh in the canopy AND a back part that can be opened when the child is napping - plus a HUGE canopy. Again flat folding but not tiny. But again very spacious.
Lastly, look at compact Cybex strollers, multiple models are nicely made and depending on the simplicity you could be ok with, you might find something that is a nice compromise for you (terrain may be a problem with the smaller model, but check the Cybex Eezy S+² perhaps for larger wheels (but less ventilation on that one).