[Bainos]

Just about completed this job myself on my 2009 Focus TDCI however i have hit a snag in the fact i can't get my accessory belt back on due to being unable to turn the belt tensioner with enough force to allow me to slip the belt back on. I'm just using a basic 17mm combination spanner to turn the tensioner but it just keep slipping off and its starting to strip the bolt head of the tensioner.. should I instead be using a 6 point 17mm spanner? or is there a special tool that is specifically for this job i.e. a 17mm spanner with an extended handle so that i can leverage it from in the engine bay?