What is this? Found in the battery compartment after draining and cleaning out the drain holes (as you do). It’s a transparent plastic tube with a right angled connector at one end. What’s it fallen off and will I die?

It’s off the Battery.

Is it a standard original VW battery or has it been replaced at sometime ?

Battery vent hose. Plugs into the end of the battery, centralish and quite high up. Other end goes through a hole in the bottom of the battery tray and vents to the atmosphere.
You won’t die, but it’s worth plugging back in seeing as you have it.

Ah… Thanks guys.