Like a lot of other I have been finding this thread very interesting and it has prompted be to do much more investigation/reading on the web with couple of books on the way too.
I thought I would share this web page that I found (getting better at this tech stuff)
http://www.wwiiequipment.com/index.php?option=com_content&view=article&id=125:british-equipment-losses-at-dunkirk-and-the-situation-post-dunkirk&catid=50:other-articles&Itemid=61
Why lists what was lost but also looks at was was left in the UK and how the equipment situation improved between 1st June and later in the year when an invasion might have occurred.
the headline numbers on the National Army Museum web site are given as:
the BEF had suffered 68,000 casualties. Most of its equipment was lost, including 64,000 vehicles, 20,000 motorcycles and 2,500 guns
This also chimes with the information in the Bovington Tank museum video (on youtube) about just how mechanised the British army was, particularly in comparison with the 'modern mechanised german army'. IIRC he listed the german army as having 120,000 vehicles for the whole army of approx 130 Division (can't recall the exact number) So 10 British divisions has the same amount of vehicles a the whole german army. No wonder captured vehicles from the fall of France continued to be used throughout the war.