Hi Lonely Boy,
Fortunately, I've never yet had a need to claim on DEPP insurance, and I'm absolutely hoping I never have to. I'm sure others on this board have though, perhaps you could try the archives? Most reports that I've read have been very positive, although having said that they're mainly from American viewpoints.
I do know that should anything go wrong, they use a local dive operation/underwater photo shop who I know to be experienced at camera repairs as the base through which all exchanges, replacements, and repairs will be done. Because I know this shop pretty well, I have a lot of confidence in the DEPP coverage. You might want to ask DEPP who their Hong Kong partners/affiliates/providers are and do some background investigation.
Hope this helps.