capital gains calculation for shares bought and sold within 30 days

HI, I bought 3009 shares on 29/5/2024, bought 3946 shares of same company on 19/6/2024 and sold 3048 shares of this company on 26/6/2024.Both purchases are within 30 days of the sale. How do I calculate the capital gains position for the sale of the 3048 shares? If I assume the 3048 are all from the 3946 bought on 19/6/2024 I have a 480 pound loss. If I use the 3009 bought on 29/5/2024 and 39 of the 3946 bought on 19/6/2024 I have a 1730 pound gain.

Hi 

Please refer to guidance at CG51560 - Share identification rules for capital gains tax from 6.4.2008: the “same day” and “bed and breakfast” identification rules and
Shares and Capital Gains Tax (Self Assessment helpsheet HS284)

Thank you