Not wishing to put a dampener on it, but I think that Royal Mail (yes i know it is a different business group) will only insure glass and china when special delivery is used.
If it were me I would check parcelforce t & c VERY carefully. If a scope was bought, as an example, they don't understand what an oscilloscope is. "Oh, it's like a television set"!
https://www.parcelforce.com/help-and...e-compensation
Rob