That is the number on my ETKA
N 013 848 7 (16x22mm) £0.41 each.
You need two per banjo connection.
However....
There is another "Seal Ring" detailed that is a smaller size
N 013 849 5 (14x20mm) also £0.41 each
Seems a mixture of the two all over the rack. Where is the leak again mate?