Standard car that holds 3 child restraints?

I will be moving to the UK in a couple of months with my 5 year old twins. My fiancé has a 9 year old son who is still in a booster. We will need a car that is wide enough for 2 car seats (high back boosters) and a booster but we would prefer a "normal" size car and not an SUV/mini-van. Does anyone have suggestions of cars that are wide enough for 3 child seats in the back? I know my car in the US (Prius) is not wide enough for 3 and most of my friends here with 3 kids have either big SUVs or mini-vans with 7 seats.

You will probably find that UK car seats are narrower, and a family car such as a Golf or Prius will accommodate 3 child restraints. I used to have a small Fiat and regularly strapped 2 infants and an older child in the back seat!

I have a Hyundai Tucson and have a full-sized Britax for my 18 month old, as well as one high back booster for my 5 year old. We can just about squeeze a third booster in the middle if we bring a friend home from school, but it's tight. I find the boosters here to be the same size as ours was in the States. (We use the Graco one.)
You're going to need to get UK-compliant car seats anyway, so you'll at least have the chance to buy seats that fit the car.

Ah, I wasn't thinking of the highjack booster, rather the one that they just sit on to elevate the sitting position.

I just bought a Vauxhall (GM) Meriva, and it's a very roomy & versatile car, without being huge.  It's very like the Pontiac Vibe I used to drive in the states, which was part of the appeal.

It definitely drives/handles like a car, not an SUV or van.  And although it seems a lot bigger, when I looked at it side-by-side with my old car (a Renault Modus-- compact hatchback), it's really only about 6 inches longer, so parking hasn't been an issue.

I'd recommend you give them a look, as it seems like it'd be a very good family vehicle.  (Just note that there's a difference in body style with the pre-2010 models, which I don't think are as roomy).

Just for comparison's sake, I posed your question to my friend at school pick up today - she's got 5 yr old twins in high back boosters and drives a Volvo station wagon. She said there's no way she could get a third booster in the back. I realize that doesn't help a whole lot, but at least you won't decide on the larger car option just assuming it will work.

Thank you all so much for your replies! Yes, I did figure out yesterday that we have to get new seats (ugh!) but I want to keep them in high back, belt-positioning boosters, which do seem to be thinner (by about 6cm each) than my current seats, so that will help with the older son in the regular booster for 2 more years.

My fiancés BIL works for Toyota, so we are hoping to get a deal there because if we can get another Prius (I will sell mine here) that would be incredibly helpful!

Just for comparison's sake, I posed your question to my friend at school pick up today - she's got 5 yr old twins in high back boosters and drives a Volvo station wagon. She said there's no way she could get a third booster in the back. I realize that doesn't help a whole lot, but at least you won't decide on the larger car option just assuming it will work.

This is very helpful because this is exactly the situation I have. 5 year old twins in high back boosters and need space for a third!