I am happy to say, after a short email discussion with Oceanic Australia, the Australian distributors of the Princeton Tec line, a good outcome was reached.
From Oceanic Australia:
I have just spoken to our senior service technician and he assures me that putting the batteries in (backwards) will not cause the module to fry. What I have learned from him though, is that our early stocks of Impact XL’s had a faulty module which on random occasions was susceptible to burn out. This problem has since been rectified in manufacturing and we rarely see returns of this model now. In fact the Impact XL is now one of our most problem free torches in the Princeton range. Anyone who has this problem would have their torch replaced.
I read somewhere:
Every company makes mistakes. It is how they fix their mistakes that sets the good ones apart.
I am happy to say that Oceanic Australia has fixed this issue to my satisfaction. In the past I have had nothing but good dealings with Oceanic, and I wish I had known they were the Princeton Distributors when I first had the problem.
I can once again recommend the Princeton Tec Impact XL LED torch.