Help please - trying to replace seat foam in my 110

[lockhart flawse]

Hi

Trying to replace the foam in the back rest of the driver'seat. I have undone the seat cover at the bottom but cannot shift the head rest to slide the cover off.

Is it just a case of brute force or have I missed something?

Car is an N reg 110 CSW.

Grateful for any guidance.

L.F.