Data Validation & Dynamic named ranges - full list not showing

Morning all, I have a bizarre problem....

Attached is the simplified sheet I'm working with. I have a named range, which is dynamic based on the first data validation list on the first sheet (Matrix) - this changes the named range as needed to one of the three lists. When selecting the named range from the name manager window, the marching ants rotate around the correct list, and all the languages. However, the data validation list on the Matrix sheet only shows about a third of these languages - not the full range... I can't figure out why, when the named range seems to be correctly defining the correct list!

Formula for the named range I'm using:

=OFFSET(Sheet1!$E$1,1,MATCH(Matrix!$C$5,Sheet1!$F$1:$K$1,0),COUNTA(INDIRECT(SUBSTITUTE(ADDRESS(1,MATCH(Matrix!$C$5,Sheet1!$A$1:$K$1,0),4),1,"")&":"&SUBSTITUTE(ADDRESS(1,MATCH(Matrix!$C$5,Sheet1!$A$1:$K$1,0),4),1,"")))-1,1)

Is there a way around this, or a better way to do this? I've tried having the data validation list dependent on the first selection, but as my Types have spaces within them I can't use them as Names, and can't display this text in any other way to show just one word (specification by the client).