Unique list of paired combinations from a list

Hi all,

i have a list of rail stations and I'd like a unique list of station pairs, excluding same-station pairs (eg. don't want Leeds-Leeds).
I have the following formula which works but does include same-station pairs.

=IF(ROW()-ROW($A$1)+1>COUNTA(Stations!$A$1:$A$4)*COUNTA(Stations!$A$1:$A$4),"",INDEX(Stations!$A$1:$A$4,INT((ROW()-ROW($A$1))/COUNTA(Stations!$A$1:$A$4)+1))&" - "&INDEX(Stations!$A$1:$A$4,MOD(ROW()-ROW($A$1),COUNTA(Stations!$A$1:$A$4))+1))

Can anyone suggest a modification which would omit same-station pairs, please?

Sample file provided.