I still don't understand the need to have lots of separate worksheets.
Have a look at the attached. This queries the data from your "temp" worksheet (based on the file location specified on the Parameters sheet), and summarizes it in one table, with a slicer to select the group. The groups have been determined using the previously discussed logic, and the Maidenhead location updated.
I don't understand what you're aiming to achieve, with your drop down box on the "Master" sheet - but now we have all the data in a model, so it's easy to create additional views / queries against it.
In terms of automation, you can update the source file name on the parameters sheet, then simply "Refresh All", and you have your latest data updated.
For reference, here's the queries used to get and shape the data:
SourceFileName:
VK Data:
Maidenhead:
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