Overall, the biggest saving was a huge 140 with the Skoda Fabia. The most expensive franchise wanted 280 from us, but a Bosch garage quoted just 140. That equates to a saving of 7 for every minute on the phone - or 420 if you spend an hour calling around.
Average savings were less extreme, but if you don't give it a go you'll never know how far over the odds you're paying.
The average savings were 32 on the Mazda, 40 on the Citroen, 56 on the Ford and 64 on the Skoda.
Almost every franchised dealer struggled to be competitive with even the most expensive independents, although there was one anomaly in our results. The second-cheapest price for the service on the Mazda 6 came from a franchised dealership (in Battens Drive, Redditch).
The quotes varied within the franchised and independent networks, too. For instance, prices differed within the Skoda network by almost 90, so it's well worth phoning three or four garages.