I have used the three tier lookup formula done by using the "Bob
Ulmas" technique that I found on the http://www.mvps.org/dmcritchie/excel/vlookup.htm
website but am trying to tweak it a bit.

I have a table with comments where not all of the lines do not
actually have a comment and the result being displayed is 0 in the
cell.

I have used this formula....

=IF(ISERROR(INDEX(O9B.Comments,MATCH(1,
(O9B.CCB=VALUE(BCostCentre))*(O9B.CCD=VALUE(BFund) )*(O9B.CCC=$C166),
0))),"",INDEX(O9B.Comments,MATCH(1,
(O9B.CCB=VALUE(BCostCentre))*(O9B.CCD=VALUE(BFund) )*(O9B.CCC=$C166),
0)))

or without the IF(ISERROR(

INDEX(O9B.Comments,MATCH(1,
(O9B.CCB=VALUE(BCostCentre))*(O9B.CCD=VALUE(BFund) )*(O9B.CCC=$C166),
0))

The formula is working (Control+Shift+Enter) but any suggestions as to
how to get rid of the 0 as a result of no comments being provided?

Out of curiousity, would

VLOOKUP({(Range1=Criteria1)*(Range2=Criteria2)*(Ra nge3=Criteria3)},....
work?

I did however, just tried a random thing which was to have a custom
cell format as "" which appears to be working..... for now.