SELECTEDVALUE not working in a summarized table

Hi

I have a 1st report page (overview) where the user can drill-through to the 2nd report page (specific) on a centre number.

Within the specifc report page I can see the drill-through has worked and the drill-through centre is filtering the specifc report as expected. I have used the SELECTEDVALUE() function to place the specific centre in a card visual.

I then create a table based on the following:
tCountOfEntriesByBandingAndYear =
     ADDCOLUMNS(
                            SUMMARIZE(
                                                Learner_Progress,
                                                Learner_Progress[certificationdate],
                                                Learner_Progress[cBandingDaysBetweenRegistrationAndCertification]
                                                 ),
                            "CountOfEntriesByBandAndYear", CALCULATE( COUNTA( Learner_Progress[cBandingDaysBetweenRegistrationAndCertification] ) )
                             )

The above table is calculating based on all centres and not just the single centre that was in the drill-through.
I have tried many variations to try and get the filtering working on the drill-through centre only but to no joy. Clearly, I don't want to hard code anything so it needs to be dynamic.

Please can you help?

Thanks.