This doesn't address Tony Moore's '83 GL wasserpumper rear seat 
question, but the subject line well describes this improvement.

  I've an '83 Westie, and when the rear seat is set-up for seat belted 
travel, the bottom cushion rests on a level surface, rather than on a 
slightly rear tilted surface.  Introducing a little rearward tilt makes 
it much more comfortable.  Fortunately, it's hinged at its rear, so 
simply introducing a 3/4 to 1 inch block to the front edge is all it 
takes to make this nice improvement which is also quite noticable while 
dining or reading there.
  A very civilized way to provide this front lift yet allow it to drop 
flat for sleeping is to secure a length of wood to the underside of the 
seat with a long piano hinge (available at any hardware store) arranged 
to hold the front of the seat up during travel, and letting it flip back 
out of the way during the bed's use.  Isn't that where you store your 
bedding?
  At first you may think you'll be loosing space by introducing one more 
claim on your Westie's interior space, but it doesn't seem to work that 
way.  As a matter of fact, the total space available for storage under 
the seat during travel is increased because the top interior surface now 
tapers up.  It's up to you if you want to play with making the top 
lockable.  Mine isn't set-up to lock and it doesn't rattle a bit.
  Now what's that line I should add to the mailer to send a copy to the 
other list.  This seems like a reasonable candidate.

  John Wakefield  "I'll miss them greatly and think of them often."