I am trying to copy a cell formula (see formula below, which is a formula
linking the value of a cell in another workbook) using Autofill but not
having much success. The cell formula is:-

='[2nd QTR Price List - Source Data.xls]A227 Grille Products'!$E$170

When I use the drag & fill cross it only copies the formula but does not
automatically change the cell reference i.e. the $E$170 should change to
$E$171.

Any help on this would be much appreciated. Thank you!