Hi,
All seats have to pass the minimum crash test, so are "safe" the problem is deciding if you think the crash test is adequate. The test is:
1 frontal impact simulation at 32mph
1 rear impact simulation at 18mph
There is no side impact test.
I would recommend you opt for a seat that has passed the German Stiftung warentest and ADAC testing. These test to 40mph+, and do test side impacts also.
It is also vitally important that your chosen seat is a safe fit in your car and is suitable for the child in height and weight - and obviously, is used correctly. I properly fitted, suitable and used £50 seat will be safer than a £150 incorrectly fitted seat with the harness round the child's waist!
More money doesn't generally mean better - the britax first class can be purchased for £100 and is fab, the Maxi Cosi Opal is very difficult to use, bulky and heavy and costs anywhere around £160+
9mth - 12yrs seats are ok... they are very unlikely to last that long however, especially cheaper ones. Child seats have a shelf life of 6-10 years. Also, because they span such a huge age range something has to be compromised - which is generally safety. You are better getting a group 1 seat designed for your child's toddlerhood.
What is the weight of your child? They can stay in a standard group 1 seat to 13kg or until their head is level with the top of the seat. Children are 5x safer being rear facing so please keep your child in this seat for as long as possible. Some seats can accommodate a child right up to 18 months +. Take a look at www.rearfacing.co.uk for more info and statistics on the safety of rear facing.
If you would like any further advice on what car seat to buy and what would fit your car, please do not hesitate to contact me.
Regards,
Kat
IOSH accredited child seat expert
Good Egg Safety Manager