After many motorcycles, different seats and different 'troosers', I have settled on this. Sheepskin patch.
Held on with wide elastic under the seat. Extra padding can be slid under...for those long days and trips! Maybe £20 - £30 for a thick peice of sheepskin. Fraction of the cost of an Airhawk, which while comfortable, moves around too much for my liking. Also cheap enough to leave on bike without worrying about theft. Made one for the Monster too. Grrrrrrr!!