We had it done both times that we bought our Zed.
I would always get it done unless they were local and I could get CS to look at the car for me but our current one was up in Scotland when we got her. The AA report was very detailed he found that a wing had been resprayed with paint depth meter!, that the battery was on the way out and all the dings and scratches which gave me good negotiating leverage. TBH without wishing any disrespect to the forum members unless your working on cars regularly (Zmanalex/CS/abbeyfield/Zedshed etc) I don't think I'd trust your opinion over the AA mechanic. I know about the issues (and discounted numerous cars before finding the current one on test drives etc) with the Zed but I don't think id be qualified or have the equipment to check a car over thoroughly and I wouldn't want someone to take my word for it either. They also pressure tested the coolant system as it was a little low in the tank so its not just a visual inspection.
I could probably drag up the AA report if you want to see the detail Joey.
Hawker