I could never understand this offer.
Many insurance policies already have breakdown cover built in. Logically, if they perform their full service correctly, the car should not breakdown. Do they not trust their own technical abilities :- ) Personally, I would prefer a €25 discount than to duplicate cover I already have.
BTW Their 'full' services does not covered the likes of pollen filters etc, which would be replaced as standard in a main dealers service. Have you noticed how the details of a service cost(s) and what is covered has been dropped from their website.