Filldown not working when only one entry

[demelzaaltitude]

Hi. I have a macro file where part of the macro is to import a CSV, add a bunch of formulas and fils them down. I've found a bug where if the csv only has 1 line, it bounces on the filldown (last line of code below). It works perfectly for all of the columns if there is more than one line, obviously if there is only one line I wouldn't need to fill down but I'm not sure how to add this exception. Thank you

    
'set fill down range
    LR = Range("E" & Rows.Count).End(xlUp).Row

'add tax formula
    Range("F5").Select
    ActiveCell.FormulaR1C1 = _
        "=IF(LEFT(RC[-1],3)=""NZD"",IF(RC[-3]<>""Account Fee"",""0.15"",""n/a""),""n/a"")"
    Range("F5").AutoFill Destination:=Range("F5:F" & LR), Type:=xlFillDefault