Hello, not sure if anyone still has an interest in this subject, but I can report that I just returned from a trip to Lord Howe Island (February 2014) and had a great time, I can recommend ProDive, they were great and I had some fantastic diving with them.
The only thing that was not good was the weather, February 2014 has been cloudy, windy, and rainy in the South Pacific and it hit me at LHI as well.
Did not make it to Ball's Pyramid as the weather did not allow it, but saw everything from turtles to Galapagos sharks, rays, and moray eels at both the oceanic sites, and in the LHI lagoon.
If you decide to go be flexible with the travel dates, there is only one daily flight from Qantas from Sydney (and occasionally another one of two from other Australian locations), and if the weather is warm or there is no wind your bag(s) may be left behind (the Qantas Dash 8 has less lift under those conditions and, if the plane is full, they start to offload bags)... and oh... be prepared to be weighed yourself with your carry on luggage in hand!
There are some really good restaurants on the island, and I can recommend Hideaway Apartments to stay, but the vibe is mostly Aussie retirees and after 9 pm the place is dead.
Happy diving /Rick