Some months ago I read a book about the formation of the Royal Society. I cannot recall the name of the book but it took us through the tough passage that history's giants like Newton et al had to overcome the philosophers. Halley is mentioned in quotes by his peers who pronounce his name 'Hawley.' The logic is that we pronounce 'hall' as 'hawl' and that's how his contemporaries pronounced it.
However if you tried to convince your workmates of this you would be laughed at

. Try saying that you saw a UFo instead - the reaction might be different.
Hope that helps!
Cheers!
Popeye.