Thanks for all your persistence!
You are right, I ahd an error in my functions, where the default $Sheet was set to a number intead of a string (expected), so it was always looking at sheet number 1, I think (your test was adding to sheet 1);
thanks again; corrected UDF as well as your etst script $var1=
; none of these shorter commands are visible until you say "_XLshow"
If Not FileExists($FilePath) Or Not StringInStr($FilePath, "xls") Then
$FilePath = FileOpenDialog("Go - Choose your excel file as inbuilt one not exists", $FilePath, "Worksheet" & " (" & "*.xls" & ")", 1)
_XLexit($FilePath); Save changes and exit Excel