Thanks for the info...I did find another post on here somewhere and whoever it was said from 1997 onwards they were optional. I know I have one on the front of my '97 but don't recall seeing any attachment points to fit one on the rear but I may be mistaken.
I've had my car for a long time but it's been off the road for nearly a year. I have some jobs to do before putting it back on the road so I'll have another look to refresh my memory when I get it out of storage very soon.