Hi,
I hope someone can help with my question.
My Mum has started looking after my 2 year old son a couple of days a week, so we looked to fit a car seat she used for my nephew which was fitted in a previously owned car in the rear passenger seat of her Cooper S Convertible. Although she does have the ISOFIX fitted we don't want to go down the route of buying an expensive ISOFIX child car seat for the sake of 2 days a week.
When fitting the car seat we have it requires the seatbelt to be pulled out fully, at which point it should start to "ratchet" back in (i.e. goes in but can't be pulled out further again) to securely fasten the seat in. However my Mum's rear seatbelts do not seem to have this function. When they are pulled out fully you can then retract and extend at will, meaning the seat isn't secure.
Could someone please confirm if this is a fault on the rear seatbelts which needs resolved or the normal function, in which case ISOFIX may be the way forward.

Thanks for reading and look forward to your replies.
Graeme