"nah they come on well before 12 months"Why would anyone sell...

"nah they come on well before 12 months"

Why would anyone sell their shares earlier than 12 months and cop a 50% capital gains tax?
Not going to happen, unless you like losing money !!

"why not sell now pocket the difference and buy back in via the rights?"

In one word, "dilution".
You only get 3 shares for every 5 you held (providing you held the shares before the Ex entilment date).

(A) So if you had 50000 shares that cost you $1.80 each ($90,000) and sold them for $1.49 ($74500) you'd lose $15500 and you'd only be allowed to buy 30000 shares (3 for every 5 you held at $1.20) for a cost of $36000 to get your $15500 loss back you'd need to share price to go back to $1.72.

(B) Or if you held 50000 shares and you sold 30000 at $1.49 ($44700 proceeds) you would still hold 20000 shares, then buy back 30000 shares for $36000, you hold 50000 shares still but you have taken some pain early.
Total costs would be original purchase $90000 less sales $44700 plus buy back $36000 = $81300 cost.
For you to break even you'd need the share price to be $1.63.

(C) Or you sell no share and take up the full entilement so original 50000 shares at $90000 plus entilemnet shares 30000 at $36000
equals 80000 shares for a total cost of $126000 means the share price would need to be $1.58 to break even, because you have avoided full dillution.

So the ones buying today for $1.49 are ahead by a mile compared to the ones that bought at $1.80 and you can see based on the math why they are getting a nice discount for anything below $1.58.
Hopefully I've done the math right, but I think you can clearly see why selling all of your shares may not be a good idea if you think the company has a future. I personally prefer option (B) because I believe you can claim a portion of your loss against and profits you have made during the year, but you should double check all of the above with your accountant.