Yeah, about 15 for a tech that has done it a few times, trust me, with normal tools you will either swear a LOT or you will un-bolt the rear shock. Getting the old one out is no problem, it is getting the bolts started again on the new mount that will drive you up the wall.
I would call ahead and have them get the part in, then schedule the service to be done while you wait, triumph will only pay the tech for 15 minutes, as previously stated, so you should be in and out pretty quick, no need to leave your bike there.