London’s Daily Telegraph has a recommendation for you:
“Sounds Scary” is a CD-based therapy product (from www.soundtherapy4pets.com) that is recommended by the RSPCA and has been shown to be effective in treating noise phobias such as fireworks, thunder and gunshots. The CDs are played at a low volume, gradually increasing over time, allowing dogs gradually to become accustomed to frightening noises.
It is important to stick to the training programme that accompanies the CDs. The reaction to the flashes should be reduced as your dog becomes less afraid of the sounds.