ok, since then i have found this macro...
http://www.cpearson.com/excel/stringconcatenation.aspx

so if i use that, i can use this formula (entered as array)
=stringconcat("|",IF(B2:I2="n",B1:I1,""))

and it works very well.

however i would really like to be able to do this without using a macro ..........

Is there any other way?

thanks
Mat