your floor choice will work great :) i have ufh in new build with air source heatpump and 21mm thick engineered wood floor (probably only carpet and solid wood would be considered less effective) and it is great, id make same choice again. i have ceramic tiles in 2 bathrooms and it definitely conducts heat better, lovely and warm underfoot when heating is running but as others have said its cooler the rest of the time. the remainder of the house just has a lovely even heat. its also very cost effective,i pay same in 4 bed, 2 bath house as i did in a previous 2 bed house (which was also new build but storage heaters). please forgive the lack of punctuation and poor sentences, this is my third attemp at posting a reply and ive lost patience writing the same thing!

Not exactly an answer to your Q but ... My builder got in a heating engineer he regularly works with. Heating engineer does the annual service for the boiler and tank and looks after the whole system, wet uf downstairs, rads upstairs i.e. same (recommended) person for install and aftercare. Afraid I've no clue about the system, as I was very happy with the engineer's rationale so ignored the brands. But thought I'd mention tradesperson focused approach as you've not had a direct answer yet.

For me it’s not worth it! Under floor heating in the bathroom is great for when you’re stepping out of the shower etc and have bare feet. As the hallway is usually a through route to other areas of the house I don’t really see the benefit of it, and for me personally I wear/put on my shoes in the hallway so wouldn’t feel the underfloor heating anyway!

UFH aside, if either floor isn't insulated at the moment, i would consider shaving some concrete off (dining) and replace the wood with steel/reinforced boards (kitchen*), to enable insulating both and thereby make them level. You can calculate the investment return with a heating bill reduction of roughly 15%. (* whether or not the void needs to be filled depends on its height. For example; before our extension we dug away the old concrete slab shed foundation and placed 25cm hard polystyrene within the new foundation rim, before pouring new concrete floors. Our living room still has a 30cm crawl space, which also ventilates the wall cavities towards the attic.) You could then decide if UFH is worth the extra, but more like a luxury, as a couple radiators can warm up the rooms just fine.