Event trigger via change in row height

see attached file
As you can see from the 2 images below, the value in cell E1 changes from 37.8 to zero when my data filter is applied.
The formula in E1 is simply = A2
So the value in A2 changes when I apply a filter to my data and it returns to the original value when the filter is removed.
(and E1 merely reflects that)
Cell E1 is incidental here - it's only there to display the value in A2 when the row is filtered.
The value in B2 is the value of A2 frozen at a point in time (created with copy & paste values)

FilteredUnFiltered.jpg

The value in A2 reflects the row's current height

I require the value in B2 to always reflect the current value of A2 in its unfiltered state, whether the row is filtered or not
And what is more important - I need to access the correct current value when the row itself is filtered
When the user changes a row's height, the historic value in B2 is no longer the one I want - it needs updating at that point.

My quandry:
Due to it being an automated change in the value in cell A2, this VBA is not triggered

Private Sub Worksheet_Change(ByVal Target As Range)
   If Not Intersect(Target, Range("A2")) Is Nothing Then MsgBox "I have changed"
End Sub

And (in any case) Target.value would be the new value (=0) after filtering which is the very value I do not want!


So the puzzle is how to update cells in column B automatically when
the user either increases or decreases the row height
without it also being triggered at the point when the row is hidden by filter
(multiple rows may be altered at the same time)

thank you