The figures for the amount of abandoned equipment do vary.
About 700 tanks, 20,000 motor bikes, 45,000 cars and lorries, 880 field guns and 310 larger equipments, about 500 anti-aircraft guns, 850 anti-tank guns, 6,400 anti-tank rifles and 11,000 machine-gun.
Source:-
https://en.wikipedia.org/wiki/British_Expeditionary_Force_(World_War_II)
over 2,000 pieces of artillery and 85,000 motor vehicles. Also left behind were more than 440 British tanks that had been sent to France with the BEF
Source:-
https://www.historic-uk.com/HistoryUK/HistoryofBritain/Evacuation-of-Dunkirk/