As a member of the IAM you get access to benefits such as discounts with various suppliers. One of these suppliers was Garmin who offered a very tasty discount on Zumo 660s of about £120. 
I decided to think about upgrading my ancient SPIII so checked out the IAM website yesterday to find no mention of Garmin.
I popped off an email and had this reply from the membership development manager.

In the past I have always had excellent customer service from Garmin but have not had to use them for two or three years; have things changed? Has their service deteriorated?
I have only ever had Garmin satnavs and would prefer to stay with them as I like the Mapsource facility but I will hold on a bit longer and wait to see who the new IAM partner will be. I guess Tom Tom are the obvious contender but are there any others likely to be in the reckoning?
I decided to think about upgrading my ancient SPIII so checked out the IAM website yesterday to find no mention of Garmin.
I popped off an email and had this reply from the membership development manager.Thank you for contacting us regarding the Garmin offer. Unfortunately due to poor quality of offer and customer service from Garmin we have recently ended this relationship. Apologies for the inconvenience. We do hope to have a new sat nav partner in the near future.
In the past I have always had excellent customer service from Garmin but have not had to use them for two or three years; have things changed? Has their service deteriorated?

I have only ever had Garmin satnavs and would prefer to stay with them as I like the Mapsource facility but I will hold on a bit longer and wait to see who the new IAM partner will be. I guess Tom Tom are the obvious contender but are there any others likely to be in the reckoning?

not sure any of the so called discounts are upto much but there again i did use them for the insurance though Bennetts where originally cheaper the IAM eventually beat it by around 10%.
think it was around £250 .