i got response from virgin today and it looks like who ever has booked a flight before there policy changes they will allow it under the old rules of 5kg per sporting bag.
this is the email.
Thank you for your email.
Each guest travelling with Virgin Blue is permitted a free checked-in
baggage allowance of 20kgs. Our current guideline is that each item of
sporting equipment is classed as 5kgs of the guests total baggage
allowance. Based on the information you have provided, the bag
containing your bowling equipment would constitute 5kgs, and your
clothing bag would be weighed at its actual weight.
I have also included our excess baggage chargers for your reference:
01kg - 10kg over free baggage allowance = $20
11kg - 15kg over free baggage allowance = $30
16kg and above over the free baggage allowance = $80 + $5 for every kg
over 16kg
Our Sporting Equipment Policy will be updated this year, however, a date
has not been confirmed. If you have already made your booking, the
current guidelines I advised, we still apply to your booking.
If you have any further questions, please don't hesitate to contact us.
Kind regards
Cassie