Narrow high back booster

[Ninunina]

Hi, I've just found out I'm pregnant with DC3 (a bit of a surprise). My kids will be 5 & 7.5 when DC3 arrives so presumably will all still be in car seats. Dd2 has just about grown out of her stage 1 car seat so I'm looking to buy a high back booster but I need it to be as narrow as possible so I can squeeze 2 boosters and a infant seat together.

My car is a BMW X3 which sounds big, but the middle seat is quite small, and I've struggled to get boosters in. I'm hoping I won't have to change my car, so any advice is appreciated.

This is one post on Car Seat Advice UK. Slightly different situation as they need car seats for 4, 2 and a baby but she suggests some high back boosters you could try.

I’m not sure you’ll fit 3 across the back in an x3, we have an x5 and are having to buy a new car when DC3 is born to accommodate 2 high back boosters and an infant seat.

(We have 3 x maxi cozi rodi)

I mean 2x not 3x!