On 12 April, General Blamey announced that the 1st Australian Corps was now the Anzac Corps. The German corps had advanced to Axios and had connected with the Italians in Albania. General List had ordered the corps "to wheel south tp Kozani". That would put them into the rear of the Greeks and British on a line at Katerini-Edesssa-Florina. They would ignore the remnants of the Yugoslav army.
The German force causing trouble for the British and Greeks had the 5th and 9th Armored Divisions and the 73rd Infantry Division. They also had the SS unit, the "Adolph Hitler Division". By 10 April, the "Adolph Hitler" division had moved into Florina. The Germans were forced to drive down poor roads that were muddy and had bomb craters. In addition, they were forced to endure bombing and strafing by British aircraft.
It seems that German intelligence was misinformed about the British divisions involved in this campaign. They might have learned in Athens what divisions they faced, but they didn't.
The attack that started on 12 April included three "battle groups". The Germans described being in a "fierce tank battle at Ptolemais. The Germans lost four tanks in this fight. The Germans mentioned taking 480 British (called English) and 40 Greek prisoners. This is based on the account in "Greece Crete and Syria" by Gavin Long.