Hi, I wonder whether someone may be able to help me please.

I'm uising the code below to try and apply, amongst other functionality a formula to a given cell, but I'm having difficulty in applying the formula.

Sub Slide1Format()
    
    Dim LastRow As Long
    
    Application.ScreenUpdating = False
    
    Const StartRow As Long = 5
    Sheets("Slide 1").Select
    
    With Range("B2")
        .Value = "Monthly Actuals Used"
        .HorizontalAlignment = xlCenter
        .Interior.ColorIndex = 11
        With .Font
            .Name = "Lucida Sans"
            .Bold = True
            .Size = 11
            .ColorIndex = 2
        End With
    End With
    
    With Range("B3")
        .Value = Evaluate("EoMonth(Today(), -2) + 1")
        .NumberFormat = "mmm yy"
        .HorizontalAlignment = xlCenter
        .Interior.ColorIndex = 37
        With .Font
            .Name = "Lucida Sans"
            .Bold = True
            .Size = 10
        End With
    End With
  
    With Range("B7").End(xlDown)
        With .Offset(7, 0)
            .Value = "BAS Consultants"
            .HorizontalAlignment = xlCenter
            .Interior.ColorIndex = 11
            With .Font
                .Name = "Lucida Sans"
                .Bold = True
                .Size = 11
                .ColorIndex = 2
            End With
        End With
        
        With .Offset(2, 0)
            .Value = "Total No. of Projects (C&R Only)"
            .HorizontalAlignment = xlCenter
            .Interior.ColorIndex = 37
            With .Font
                .Name = "Lucida Sans"
                .Bold = True
                .Size = 10
                .ColorIndex = 1
            End With
        End With
        
        With .Offset(3, 0)
           Selection.FormulaArray = "=SUM(IF(FREQUENCY(IF(IFPRLOB=""Consultancy & Requirements"",IF(LEN(IFPPN)>0,MATCH(IFPPN,IFPPN,0),"")), IF(IFPRLOB=""Consultancy & Requirements"",IF(LEN(IFPPN)>0,MATCH(IFPPN,IFPPN,0),"")))>0,1))"
        End With
         
    End With
    Columns("B:L").AutoFit
End Sub
This is the line of code I'm having difficulty which I've put togther from posts I've read on this and other forums:

With .Offset(3, 0)
           Selection.FormulaArray = "=SUM(IF(FREQUENCY(IF(IFPRLOB=""Consultancy & Requirements"",IF(LEN(IFPPN)>0,MATCH(IFPPN,IFPPN,0),"")), IF(IFPRLOB=""Consultancy & Requirements"",IF(LEN(IFPPN)>0,MATCH(IFPPN,IFPPN,0),"")))>0,1))"
        End With
Manually entered, the formula works fine, but when I run this I receive the following error:

Run time error '1004' Unable to set the FormulaArray property of the Range Class
I just wondered whether someone could look at this please and let me know where I've gone wrong.

Many thanks and kind regards