Car seats in hire cars

[lagartija]

We're hiring a car in Holland next month and will need car seats for DS (4) and DD (1). DD weighs 9.7kg now and is in a (rear facing) group 0 seat in our car. DS weighs about 16kg, 17kg max and is in a group 1 seat. The hire companies all seem to say that DD should be in a group 1 as she's more than 9kg and a yr old and that the group 1 is for 1-3 yr olds and that DS therefore should be in a group 2, but he's not 18kg, which is the weight it states for a group 2 car.
I can just book them a group 0 for DD and a group 1 for DS, can't I? I won't get anyone being funny when I pick up the car, will I? i thought group 0 wet up to 13kg anyway???

Check with your airline, we had a seat for dd2 and were able to take her stage 1 car seat on the plane on her seat(with her in it), only works if seat can work with lapbelt, but safer than being just in airline lapbelt, we put a booster seat in dd1 hand luggage, and saved ourselves the 80euros that they wanted for the pleasure of hiring seats which we didn't know the history of (and looked quite grotty when we saw them). Was a bit of faff carrying them through airport though. Stage 2 is from 15kg.

DS's group 1 is a maxi cosi prorifix and weighs a freaking ton! There's no way I'd be taking that on the plane! I suppose I could theoretically take the group 0 on the plane for DD, or check it in, but wouldn't want it to get damaged.

We have one of those too, and yeah couldn't carry it on, it was another of our car seats, a britax which we carried on. Wouldn't work on stage 0 as needs to work with just lap belt. Don't check it in, those guys are training for olympic shotput!

Most stage 0 go to 13kg, but think some were only up to 9kg. There is an overlap between stage 1 and 2/3. 2/3 is from 15kg. A stage 2 should be safe, as long as he doesn't undo seat belt.

so, do I book a stage 1 for DD (9.7kg)?

I'm amazed that your 1-year-old is still in a group 0 seat - that's the little bucket seat that you use for newborns - yes? It's not just weight BTW - it's length. Is her head still safely within the confines of the seat?

Dd2 was in stage 0 until nearly 18 months, and even then was not quite big enough but moved her on. It should be purely on weight, and shops aren't supposed to sell a new one unless they are heavy enough. Have had same issue with her going from stage 1 to stage 2, she is 5 and kept trying to get out of stage 1, is happier in big girl seat and doesn't mess with the belt, was a good bribery tactic to get her to eat more high fat food.

Rear facing is safer (except of course for airbags). Having said that, for OP I would order stage 1 in case the provided seat is only tested to 9kg. At 16kg either should be fine, as is between the two.

juneau her head's nowhere near the top and she's not teeny either, 50th percetile for weight and height.
Good idea bunnies will go with stage 1 for DD. Might go for stage one for both of them so that DS is in a harnessed seat.