I've just used Parcel2Go to book a Hermes collection. (Not for G Scale items.)
One of the optional boxes to tick was for insurance. Unticking this box gave you a note that they recommend you purchase insurance. So the small cost involved, I did.
The thing that gets my goat is all these extra costs you pay for after they give you a cheap quote, but I guess all the parcel firms do so?
I have booked collection for Thu 10 Dec and will see how good the Hermes service is for myself....