=SUMPRODUCT((A2:A6<"")/COUNTIF(A2:D6,A2:D6&""),--ISNUMBER(MATCH(A2:D6,ConditionRange,0)))=COUNT(Con ditionRange)

where ConditionRange refers to a range housing the values whose
existence in A2:D6 you want to check.

Or

=SUMPRODUCT((A2:A6<"")/COUNTIF(A2:D6,A2:D6&""),--ISNUMBER(MATCH(A2:D6,{1,2,3,4,5,6},0)))=6

if you refer to the values of interest by means of a constant array like
{1,2,3,4,5,6}.

nospaminlich wrote:
Just a thought...

I've adapted this so I can use it for columns as well as rows but is it
possible to set it so it covers a range of say A2:D6 e.g. a 4X4 area
containing the numbers 1 through 16?

Thanks a lot