In message , at 12:22:00 on Tue, 5 Jan 2021,
NY remarked:

The first name is the one that sticks in people's minds. If they'd
wanted to called it the Elizabeth Line, they should have used that name
from the start. Having first called it Crossrail, that's the name they
should stick with.

Like for Opal Fruits, Marathon and Jif.

I hadn't even realised that the New Severn Bridge was now called the
Prince of Wales Bridge.

I've never heard a member of the public refer to the Dartford Bridge as
the QE II bridge. Then there's "Big Ben" (yes, I know that's the bell)
and Elizabeth Tower.

At least we haven't adopted the US policy of naming everything after
the full name (including the middle initial without which no official
US name is incomplete!) of a sponsor.

Boston Airport is either "Boston Airport" or "Logan Airport" as far as
I'm concerned, not "General Edward Lawrence Logan International
Airport".

Why *do* Americans insist on using their middle initials/names on
official documentation? Does "John H Smith" sound more impressive than
"John Smith"?

Because of the same reason as below. Hence George "W" Bush for example.

And why do so many Americans have Roman numerals after their names? Is
it because children are named after their father, grandfather and great
grandfather (all called John Smith, distinguished by I, II, III and IV
suffix) rather than being adventurous and choosing different forenames
for each generation?

It's just a cultural thing, like many Europeans have names like Magnus
Magnus*son*, and innumerable similar Slavic suffices.
--
Roland Perry