Just booked a an hotel for Hull today.
Before Ian gets here!
Does Ian not follow the conventions of the English language?

Which convention? ‘An hotel’ has largely been superseded by ‘a hotel’, but I would say "a history book" but "an historic event."
Guess it’s your choice. 😊
The convention is it's
an if the following word begins with a vowel sound and does
not have the stress on its first syllable. It's
a if the first syllable is stressed.
e.g. a
hospital, a
history book; an ho
tel, an hist
oric event.
It's vowel
sound that matters, not spelling, so for instance it's never an university. Whether "hotel" qualifies is debatable, I see that Grammarly objects to "an hotel".
Always remembering there is a difference between the conventions of grammar and good English usage.