Access rear seats

[Liss-DS3]

Help!
My dog chewed through the middle seat belt which needs replacing ASAP before the MOT. However, I can’t work out how to access the mechanism for the middle seat belt as it seems to be housed inside the seat. Have I got the remove the seat cover and if so, how do I do this as it seems to be sewn together?!
Has anyone done it and could give me some pointers?

[Chris_Blue]

you may have to remove the rear bench seat to get to the mechanism