Tbh just stick a Bowden's kitchen in, something basic that won't date and continue the flooring.
Put in a large shower room downstairs, something modern and you have a down stairs clickroom come extra shower.
Put in a decent en suite to the bedroom
Knock through the main bathroom and WC to make it all one and add a door to the main bedroom so it is a family bathroom and en suite - bit like a jack and Jill bathroom
Lose a bedroom on the second floor and make another bathroom.
You then have 5 bedroomed 4 bathrooms house with two ensuite