Just before the 2000 Sydney Paralympics, his classification was changed from F56 to F55, and he was told that he had been competing in the wrong disability group for his entire career. He did not win any medals at the 2000 Games. Giddy regretted his disqualification by video footage in the shot put at the Sydney Games after throwing a world record. In 2002, while training in Germany for the world titles in France, he cracked his sternum and hurt his back in a fall. He then prepared for the 2004 Athens Paralympics, but the back injury had flared up again, and the plate in his back had broken in half. He retired in early 2004 due to the injury. He came back for the 2006 Melbourne Commonwealth Games, where he came seventh in the seated shot put, and was Australia's oldest ever Commonwealth Games athlete. At his farewell dinner in 2004, Chris Nunn, Head Coach of the Australian Athletics team at the Sydney Games, said "Whilst you may have travelled thousands of miles in economy class, your contribution has always been first class".