Since we converted our garage my wife has decreed that my punchbag must be hung outside. I've got a bracket but I'm not sure how best to fix it to the wall. The punchbag weighs about 60kg (it used to hang from the garage roof joist) and the house is timber frame with cosmetic facing bricks.
Have you had a chance to have a look at the DIY Projects area: http://www.diydoctor.org.uk/projects.htm especially the project entitled "Fixing (General)" You may find a suitable item here. If not contact the Site Box as they may be able to assist you further.