Lea and Perrins Worcestershire Sauce 290g

Once the 1 gallon jug is opened and a portion used does the remainder require refrigeration?

This list is for 1 gallon or 3 gallons? the description said "3 pack of 1 gallon plastic jugs"

What is the best by date on this product and is it the thick sauce?

Just to make sure this is the PROPER English version, not that rubbish american one that uses corn syrup? Please list ingredients as I check labels!