It has been 8 or so years since I did anything in excel, please excuse
the simple question.

In cells a1 and b1 I have a string stored. In cell c1 I would like to
have a function I have written ( = Module1.func(a1,b1) ).

Function func will return a value to cell c1.

I must be doing something stupid because excel flags the cell with a
#NAME? error.

Can someone explain how to make this work?

Thanks in advance, Bob.