That's a very good implementation of the game - nice job!
The only minor complaint I have is that the score disappears as soon as the game is finished, it would be nicer if it stayed (but perhaps in a different colour) until a new game is started.
In terms of the code there are a few bits that can be shortened/simplified, one of which is the repetition of code in Clicked. The code for rows 3,4,5 are identical, so rather than have a Case for each one you could use a single case for all three, eg:
alternative syntax using a range:
Case 5, 4, 3 'Bottom/second/third row of layout
As most of the code is also identical for row 2, you could even merge them all, like this:
Case 3 to 5 'Third/second/bottom row of layout
Case 2 To 5 'layout
CellRef = Xlate(Target.Column, Target.Row)
Range(CellRef).Interior.ColorIndex = 10
If Target.Row = 2 Then 'Top row of layout
Finished = Finished + 1
If Finished = 3 Then 'All 3 cards at the top of the peaks used
Score = Score + (Unused - 11) 'Bonus based on no of cards unused
[A3] = Score
[K7] = ""
Range("K7").Interior.ColorIndex = 10
Else 'other rows
Most of the routines in Module11 aren't really needed, as there are already equivalents built in (which should be faster than yours), eg:
Replace: Replace (but slightly different behaviour to your version, so probably not apt).
FindNumber and FindLetter can be simplified slightly by replacing this:
Asc(Mid(Ref, f, 1)) <= 57 And Asc(Mid(Ref, f, 1)) >= 48
IsNumeric(Mid(Ref, f, 1))