How can I fix Drenching Leak from a Triton Opal 10.5kw?

My son had a 10.5 kw Triton Opal shower fitted about two years ago, but, within six months, it developed a tremendous drenching leak under the casing, which cascaded down the supporting back wall, with nothing flowing from the shower head.
To see if I could detect the exact source of the leak, I had to remove the front cover and use the ceiling switch to operate the shower pump. The water gushed with such profusion - like a full bore tap, over all the electrics, such that it was impossible to see from where it came. After switching off elecricity I could still not see where the rupture was, although it must be sizeable.
Any suggestions please?

David Garrett
May 2008