What Car Q&A - Can I protect my seats from damage?
Putting a layer of carpet under the car seat is potentially dangerous. If it’s too thick, it could raise the seat too high. Or, if it’s slippery it could allow the seat to move around.
There are specially-designed products to do just what you need, however, such as the Sunshine Kids In Car Grip-It Mat (£9.99 from Amazon.co.uk) and the Neatseat (£24.99 from Mothercare).
Both are safer ways of keeping you child seats in place, without them damaging your car seat at the same time.