Mudpup, your child will be in the last 2 weeks of their time at Primary school and their education will not be affected by missing them so don't worry about that. Be honest with the school, you won't be alone in wanting to do this but they may have a wierd policy about only authorising so many kids out of school. At this late stage I wouldn't worry about attendance either, it will be included on the OFSTED report for the following inspection/year but who gives a damn what they think? It shouldn't be classed as an unauthorised absence anyway unless they say no and you go anyway…by saying yes, the absence is authorised (are we now saying that pre-arranged dental/doctors appointments are unauthorised?.
However, it is their last 2 weeks at that school…ever. Are they going to miss some important stuff that all their friends will do, celebration/awards stuff, residential or day trips, etc? These may be the things they remember about their time at the school.
Otherwise, go…have fun, teach your child about the world and let them teach you about theirs, spend time with them and enjoy their company and recognise that a major chapter in their life is ending – big school here we come.
PS. As a teacher it's always great to hear holiday stories from kids (no really I'm not being sarcastic), we chose our jobs and the limits it puts on when we take ours hols, they didn't chose to have to go to school.