Stop updating values pop-up when updating formulas

Hi Gurus,
Hoping someone can assist as all other searches/fixes don't seem to work for my spreadsheet!
I have a workbook that searches for and grabs values from closed workbooks with variable naming convention dependant on a cell value in the format "MmmYY".

I have attached a small sample- the actual workbook has over 100 lines and 15 colums with formulas to return data.

The updating of this workbook works with no issue using really simple VBA:

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When i try and clear the data using :

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I get the "update values" pop up for each cell which i am trying to remove.

I have tried the below pieces of code but these didn't work for me and the update value box still appeared.

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and :

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Hoping somone can shed some light on where i'm going wrong?

Cheers,
G