I read that too, decided that someone had come up with it as a theoretical excuse for claim refusal, rather than anybody having had experience of it happening. Hard to argue that it is not a modification though, it might even stand up in court, although it would normally be very hard for them to show that the modification had resulted in, or affected, an accident claim!
You could go for an OBD hardwire kit instead, I don't think that has the same problem, since you don't pull out a fuse and modify the fuse holder using the fuse tap. The OBD hardwire kit is simply plugged into a socket provided by the car manufacturer.
Adding a camera as a permanent install is normally considered a modification, since it may affect the chances of the car being broken into, but it may reduce the cost rather than increase it, more likely has no effect. I'm not sure why they said that using the lighter socket didn't need to be notified.
Standard cover normally only covers personal belongings up to £150, so if you want your dashcam covered under the insurance, you may want to increase that cover, so definitely need to tell them, however it is installed.
Fitting a cheap suction cup mounted dashcam, and dangling the cable rather than installing the cable behind the trim, is probably OK without notification, since it is not permanently installed.
Best to just tell the insurance company next time you renew, probably wont affect the cost, unless you are installing something expensive and want it covered for theft/damage.
