When I type `C-u C-x =' on the character `£', I get
something like this:

character: £ (2211, #o4243, #x8a3, U+00A3)
charset: latin-iso8859-1
(Right-Hand Part of Latin Alphabet 1 (ISO/IEC 8859-1): ISO-IR-100.)
code point: #x23
syntax: w which means: word
category: l:Latin
buffer code: #x81 #xA3
file code: #xA3 (encoded by coding system iso-latin-1)
display: by this font (glyph code)
-apple-monaco-medium-r-normal--13-130-72-72-m-130-iso10646-1 (#xA3)

Why is the code point #x23? Should it not be #xA3 in Latin Alphabet 1?
Because when you click on the #x23, the character list you get shows
the code point as being #xA3, which is confusing.

Also, what are the first three numbers in parenthesis on the
`character:' line? Are they code points of some charset? (I
understand that the fourth number is a Unicode code point.)