which car seats are the smallest, for 2 yr olds and 5 yr olds?

[mummykanga]

I am trying to find ones which will fit the very small seats which flip down in the boot of a mercedes e class estate... our maxi cosi is enormous in comparison. Britax Prince and kidplus or adventure look small-ish at around 45 cm deep and wide...anyone got any better ideas? so tricky when you don't have the car to take with you to the shop!

Britax Prince narrowest I could find for the 2yo.
Very basic booster for the 5yo?

we have the britax eclipse (same seat as the prince but you can recline it by pulling the button at the front,the prince has to be fitted either reclined or upright) and also 2 britax hiliner/adventure seats in our car,we chose these because they are narrow and they fit well next to each other because of the shape of them.you should be able to try both of these seats in halfords (the hiliner/adventure is on offer in halfords atm too)

trunki boostapak for the 5yo is very narrow (but good)