 Complete the following phrase:  The battalion started combat on 20 May when they came under shell  mortar fire. On the 22nd the Bn retreated to Coutrai, and then on the 23rd to hospital for incurables at St. Andre near Lille, 160 casualties were reported here. On 24 May the battalion was sent to Viller Berquin, and on the 25th to Strazeele where they encountered German tanks and took heavy fire. On the 25th26th they moved on to Rouge Croix, taking a defensive position facing Hazebrouck, then pulled back to Mont des Cats. On the 27th they come under heavy fire from dive bombers and shells. Finally, on the 28th they retreated via Poperinghe, to Bray Dunes from where they were eventually 