You can find it on SHEIN aswell
I bought a big button down one from primark x
I ordered this one - it hasn’t arrived yet so can’t speak to quality but it matches your requirements! https://happymama.co.uk/products/hospital-bag-maternity-skin-to-skin-delivery-nursing-nightshirt?_pos=9&_sid=2748a26b1&_ss=r
I think I’ve seen a couple on PLT, I’m planning on wearing a nightshirt which buttons all the way down with a seamless bra x
I found some maternity ones on boohoo with buttons and just sized up xx