I am attempting to get a macro to copy an IF() function using a
relative cell address

Range("K65536").End(xlUp)(1, 2).Select
ActiveCell.FormulaR1C1 = "=IF(RC[-1]<1000,""F"",""H"")"
Selection.Copy
Range(Selection, "L15").Select
ActiveSheet.Paste

I am expecting to see either F or H in the cells but I am seeing the
formula =IF(RC[-1]<1000,"F","H")
I suspect that the problem is something to do with the relative cell
reference as the function wizard in Excel claims this is "Invalid".
Two hours searching the archives has not proved fruitful.

I am frustratingly new to all this so any assistance would be much
appreciated.