I can not get my head around how a family could make this home work for them
Funny. Our house has this layout and we (plus many others in similar) find it works very well. We are a family of 4.
Ground floor bedroom at front - ideal for a pre-teen or teenage dc. Got it's own bathroom, so means a lack of queuing for the bathroom. DC gets their own "space". If it's the same as ours, the downstairs bathroom is actually a "Jack and Jill" bathroom, accessible from both the bedroom and the hallway, which means it can be used by visitors who don't need to be given access to the second floor, keeping that area of the house more private;
Ground floor bedroom to rear - ideal as a study when dc are older, either for adults or so that dc have a quiet space away from the rest of the house/distractions for doing homework. When dc were younger, it was used as a playroom to keep the clutter of toys out of the study. As a playroom, it can open out into the garden for dc to play and you can sit in here to watch them. We used to have armchairs in there, bookcases and a TV. Now that the dc are older and it is used as a study we have a sofa bed in here for guests (usually kept as a standard sofa). Because the utility room is downstairs there is little need to be pottering around in the kitchen doing "jobs" (or maybe I'm just not a pottering around in the kitchen type of person). Most 4 person families don't use their 4th bedroom as a bedroom anyway, even with a more conventional layout;
Living room/kitchen - fairly standard. Ours are quite large. If yours are the same proportions, the photos don't do them justice. We have a 6 person kitchen table in our kitchen (for everyday use), plus a 6 person dining table in the dining area of our living room (for when we have guests);
Second floor - main bedroom, fairly standard, ensuite. Again, if yours is like ours, the photos don't accurately depict the size;
Second bedroom - for another dc, or large enough for 2 young dc to share (our upstairs second bedroom was large enough for two single beds with plenty of space to spare), especially if you have a dedicated playroom downstairs, so they don't need to store their toys in their room.
Main bathroom, which means whoever gets the second bedroom upstairs doesn't have to share the bathroom as the other bedrooms all have en-suites.
However, the layout works especially well for a 4 person family if you have pre-teen or teenage dc as each person can have their own bedroom and there's space for a dedicated study too. It's not conventional, but actually very versatile.
I should say OP I think it needs to be clearer on the details what parking space you have and the fact you have a garage. A house without a garage would be an absolute no-no for me, but it's not clear from the pictures and people won't always read through the text.