If considering wood you could get unfinished wood installed. Companies such as Wood Floor Accessories are a great supplier. Having it finished on site means a finish can be picked that works for your home. Each home has variables such as pets, different traffic and the owners desire to maintain the flooring or aversion to maintenance. Having wood finished on site has advantages. You can pick the highest quality product that works for your budget. The range of finishes available is quite wide. A professional company will try to understand your home and recommend the appropriate finish. They will also understand how easily the finish was can be renovated in the future. Amtico is an extremely robust product but being plastic, is just plastic flooring. It has its place, as does wood. In areas that have plenty of light surfaces, scratches show very easily on Amtico, Karndean etc. The manufacturers push a polishing maintenance product on consumers. However, this needs to be stripped and reapplied on a regular basis.

https://www.loveskirting.co.uk/flooring-thresholds-c17/by-product-c29/ramp-section-c43/solid-oak-ramp-section-threshold-0-9-metre-p121

We are coming to the end of a house renovation and we had wet UFH installed in all our rooms. It is a bungalow however, it is very unusual property with rooms below the bungalow so it is like a house in some respects. We have a mixture of solid floors and suspended timber floors and couldnt have a screeded system because of the weight. We had an ESP overlay board system installed and have found it to be very effective. Ours is run off an ASHP so I cannot tell you how it would work off gas central heating. Our UFH is on 24/7 controlled by thermostats in each room/area. We did install internal wall insulation on all of the external walls and window reveals and voids beneath the floorboards where possible and my understanding is that this is key to efficient and cost effective UFH.

Rinked, I also considered that, but the table and chairs would block access to the back garden. The front extension would significantly block most of the south-facing light in the living area, the back double doors, are north-facing so they don't bring in any light. So while I agree that you need some sort of entrance into the home, The front extension is a mistake in my opinion. In regards to the comment of keeping the passage, yes it's good to have, however, soo many people who live in terrace houses don't have that option and I don't see that as a significant issue.