Snap, had this on our AUM last year. Coolant flange. This is a common problem.... The o-ring that seals it to the head degrades from the heat and starts to leak. Flange 06A121132AP (£12)Drain the coolant. Get the battery and airbox etc out. Its kinda fiddly as the access aint great. If you had it in mind to delete the SAI combi-valve etc its a good time to do it with this lot off.Make sure you clean the head up real well before re-fitting the new flange
the secondary air pump? if so i did the fix on that a while ago,is there a readme/howto?