Thinking about it - am assuming you've not got a bottomless pit of money, so I was told when doing work, moving ovens and toilets are expensive. If you can keep those in current locations, its easier.
So downstairs : take out the wall between the lounge and kitchen, making large kitchen diner living room, with an island around where the current wall is, putting your stove on the island.
Take out the wall between the utility and downstairs loo and make a shower room.
Move the back wall of the garage forward to give a wider corridor and make that a utility corridor. Put a door from current garage at the bottom of the stairs (near front door), turn that room into a study or playroom.
Use the current dining room as a grown up drawing room, unless you want dining room and kitchen diner (most people I know with 2 dining tables end up only using the posh one for Christmas and easter, always feels a waste of a room unless you host a lot of people who are too posh for kitchen table meals).
Upstairs:
options - 1) turn current family bathroom into 2 en suites for bedrooms 1&2, leaving 3 and 4 to use the new downstairs bathroom.
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turn current bathroom into a big fabulous en suite for bedroom 2, then turn half bedroom 4 into a new family bathroom (which think is directly over the current downstairs loo and utility so should be relatively easy to sort plumbing), using the other half as a en suite for room 1. This option drops you to 3 bedrooms plus the study/playroom downstairs you could sell as a 4th bedroom but it's unlikely many will see it as that.
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turn half bedroom 4 into en suite for bedroom 1, making bedroom 4 into a box/single bedroom.
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go into the loft and put a bedroom and bathroom up there. You might be able to get 2 decent sized bedrooms plus a bathroom up there, depending on your roof shape.
Basically, wanting 3 bathrooms upstairs in a 4 bed house is going to cost you living space. If you have an eye on resale, there's a point when adding bathrooms doesn't add value if you take away bedroom space. It's more how you want to live.