The 44 pattern metal bottle was issued with the 44 pattern webbing which was officially the jungle issue webbing through the malaya conflict, The lighter webbing material was ment to dry out quicker and was rot resistant, and the metal bottle kept the water colder. When the 58 pattern webbing came in it was issued with the plastic bottle pretty much straight away, however the 44 pattern webbing was available for issue well into the 60s even though once 58 patt came in most stuck to the later issued gear. This meant the 44 patt gear sat around in stores. Most out of choice would aquire the 44 patt cover and bottle as it came with a metal mug that allowed you to bin the plastic mug and bottle and mess tin combo, it also allowed the use of the better cover, the 58 pattern one being prone to shrinking and becoming the krypton factor of tasks for the average squaddie to get the bottle into the shrunken canteen cover. the metal bottle allowed for heating in the bottle and could be used as a hot bottle in the sleeping bag. The draw back was they burst in freezing conditions. The 44 pattern webbing inspired the famous SAS webbing and was the basis for early versions of the webbing type.
The green bottles apparently were made by many makers, the black one was then made by one, OSPREY.