There are large scale investors who balance long and short...

There are large scale investors who balance long and short positions across market sectors(eg one of the Morgans family of like names - i forget which one in particular). so it may not just be WBT, but WBT in opposition to some others.

When WBT made the last CR there was a lot of shorting going on just prior, it could/would have been advantageous to those participating, but was it actually them doing the shorting - just speculation - no way of knowing?
What you can do is write to ASIC if you have concerns about the manner of shorting (i did about that).

What can WBT do, not much. To start buying back shares is expensive especially when you have plans for capital spending, but to do it occasionally might annoy the shorters and discourage them from rolling over the shorts.

What can we do. Buy during the close. That won't help much, but the closing price influences decisions for the next day.

The only systemic way of partly dealing with shorting is to negate spoofing, which is sticking in sales of 1 or a few shares in any gaps in the market at the lower bid price. How to do that...write to your local MP and to Senator Bragg (google Senate committees on financial services).