The key point of the document is in one of the opening statements. I don't have it to hand but it basically states that member states have the autonomy to regulate above and beyond the limits imposed within Sub Part Q. For the UK there is nothing to stop the CAA overlaying Sub Part Q with CAP371, hence nothing in the UK changes. What will change is EU member states who have limits that are less than those imposed by Sub Part Q, in particular those member states that currently have no FTL limits for cabin crew!
In this case, surely the efforts should be directed to the CAA to ensure that they exercise their rights and impose the limits currently in place in the UK.