After only owning the car a couple of weeks noticed i have been getting back ache, put it down to the vectra not being as comfy as my astra H Sri seats.

After closer inspection to my right hand side towards my door the sponge has completely either gone or sunk into the seat! No cushioning at all at that side.

Whats the cheapest way to rectify this? A new seat from a scrapyard? How easy are seats to remove and fit? Would Vectra Sri fit?

Cheers for any help