Adjusting buy prices on repatriation

Hi after living overseas for a number of years, I returned to Australia. From a tax perspective, this triggered a reset in the valuation of my shares to the buy price on the date of entry to Oz. When I now sell any of these shares I need to calculate CGT based on this new price, not my original buy prices. Is there an easy way to do this in Sharesight? I’d rather not just go back and have to change each buy price, as there’s quite a few transactions. I thought about using the “adjust cost” base function, but not sure if this would work given that I will need to also set the date of acquisition of all my shares to the repatriation date.