I have a spreadsheet that I update monthly. A column of cells contains a
formula that links to a previous spreadsheet something like this:

=vlookup(a1,'[OctoberFile.xls]Sheet1'!$A$1:$K$100,4,false)

If I put text in cell B1 "OctoberFile" I would like the [OctoberFile.xls]
part of the formula to change if I change the content of cell B1 to
NovemberFile so that it links to another file called NovemberFile.xls.

Not sure if I have explained this very well does does anyone have any ideas
without using code?

Thanks,

Andrew