If the proposed changes to the 2022 HL Leaving Cert Accounting exam mirror those that were made to the 2021 HL paper, I recommend that you pay particular attention to the following topics for your mock exam, as a practice run for June:

Section A:
Q1 Final accounts of a Sole Trader
Q1 Company Final Accounts 

Section B:
Q5 Interpretation of Accounts

Section C:
As many topics as you can cover. 
I recommend that you focus on Costing and Flexible Budgeting as they have been combined in Q8 in the past. 

You will have to answer a second question in Section B for your mock exam which may not be the case in June, so study up on areas you are especially comfortable with and can fit in without adding greatly to your workload. You should ensure you are familiar with Incomplete Records at the minimum.