See, I always thought they were called a connector bend no.4
You're definitely right.
The large bottom part is definitely called a 'Connector Bend no. 4' (aka an Elephants foot).
I've known that was its name for sometime.
It was the top cover I was unsure what it was called until I had to order 1 recently.
That part is a 'Cover 101A' which is probably where the other person's confusion came from.
Are they something the average engineer has in their van?
Can you think of a reason why my engineer took mine, apart from the fact it was a bit fiddly to put back on?