The battery should be accessible from the passenger seat rear footwell. There is a shaped panel that can be removed to reveal the battery and allow the retaining frame to be loosened. That on my four seater anyway (1990 version. In mine its just held in position by the surrounding carpet.

Afraid I cant advise on the more thorny issue of the shock absorber.
John

1990 Plus 4 4 seater
Ivory with Red