I live in the UK and there are no expiry dates on car seats hence why I do not understand it. The UK laws are generally very rigid - we have to have our children in some form of seat until they are 11 years old so if expiry dates were a neccessity then I assume they would apply here.
You have no expiry dates on car seats? So, what's stopping someone from using a seat that's 20 years old? That is scary...
Just because there is no law about it, it doesn't mean it's acceptable to follow that. 7 years old is very old for a car seat.
Canada and US are very rigid about car seats, so obviously the UK isn't rigid enough if they aren't recognizing the fact that car seats break down. Are your seats made out of plastic too? I'm just amazed by this info...
Best of luck with your new babe! Tiger