We were told in year 12 at a parent's meeting that because the trend for gap years is increasing year in and year out especially recently the school will not be doing references for them after they left school.
So who would add the compulsory academic reference... their primary school? 
Gap years happen for all sorts of reasons. DC has not 'demanded' a reference be added. This year only 4 pupils have had gap year at DC's school this year, 2 of whom were medical school reapplications. Should they be penalised by having a school refusing to add a reference because they achieved top grades but did not get an offer in Y13? Luckily DC's school is happy to do a reference, it will just be charged for even though the reference is on file.