Second isn’t a new build though is it? It‘a remodelled mid-late 20th century (unspecified - hard to tell as it’s been re-rendered, but the roof doesn’t look new) - which should mean the proportions are probably a bit better than the average new build.
IMO of these two I’d choose the second - layout looks better - two living rooms, no downstairs bedroom, reception space and kitchen next to each other which is much better with kids, detached, more space to remodel/extend if you ever wanted to, garden is also lovely. First has lots of character but the layout wouldn’t work for me, third bedroom upstairs is tiny and semi-detached.
I say this as someone who as a rule much prefers period properties, but recent househunt has taught me never to exclude anything on this alone.