very strange letter from biota !!, page-6

I suspect that they need your latest postal address to be able to mail you a cheque for the 11+ cents return of capital.

In the event that the ATO deems the amount to be an unfranked dividend, Biota will also request your Tax File Number (applicable to Australian resident tax payers) so that withholding tax will not be withheld. You need not disclose your TFN, if you so wish, in which event, 46.5% of the gross dividend will be handed over to the ATO but you will be entitled to a tax credit for the tax amount so withheld.