I'm looking to check in a few cardboard boxes full of various pull up banners. If the boxes are within the BA luggage size and weight limits, will this be accepted?

Do I need to do anything to them? They are fairly secure and have been packed by the company who produced them to be carried as hold luggage, however I am unsure how this works? There is one box the size of a suitcase and a few the size of say skis.

Any advise before we get to the airport would be great