Typo errors

Despite checking and re-checking the manuscript numerous times, you may still find the occasional typo error.

Unfortunately I spotted two:

-page 220, under "1936", "Hawker Fury I" - 2P and 25PM under "year" should read "1936-41"

-page 220, under "1936", "Blackburn Shark I" - 36PM under "year" should read "1936-41"