VLOOKUP Not Finding Numeric Values

[watchouse]

Hi Everyone,

This is driving me mad! I have a DATA worksheet containing alpa numeric and numeric references both formatted as such. When I try to VLOOKUP the numeric value, it does not find the value although I know it's there. Even when I put an apostrophe in front of the number on the MAIN SHEET, it still does not find it.

I'm getting my knickers in a right old twist and will probably kick myself if it turns out to be something really simple.

Any help would be very gratefully received.

Andy