Age & budget?
Alfa Giulietta is a bit bigger, available as a 1.4l 170bhp petrol or 235bhp 1750cc petrol and various oil burners which can have a "TCT" dual clutch auto. The TCT models tend to be quite high spec so folding mirrors should be easy to find. Heated seats is actually the slightly tricky one, it seems most people don't bother in these low end cars despite their being both single and multi level heating options. I find that odd, unheated leather seats in the winter is pretty bad.
The Mito is closer to Polo in size, but only comes in 3 door so I guess that is out.
I find the styling a challenge myself, but Audi A1? Probably a Polo underneath