Mounting A Punch Bag

Hi, No I'm not getting the wife to hook me up:) but I need to put her new toy up (seen in image below). Well as least I will be able to go to work now without so many bruises. The punch bag weighs 14kgs and I want to mount it in the undercover area we have. The batons (I don't know the real name) going across are supported by the metal plates as arrowed - they are also on the opposite ends. Do you think that hanging - the punch bag to just one of these is OK or would it be prudent to...

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