In fact I have. All they can do is test health of the battery itself, which their diagnostics report as fine. That of course doesn't tell the whole story, as you could have a healthy battery but still have excessive drain coming from a sensor or software bug - but they don't appear to have a way to pinpoint what exactly is using all that battery.
I'm returning my 38mm Watch tomorrow and will be waiting until July for a 42mm replacement to arrive...
I hope the next one works better for you mate