Glad it’s working for you now.
In case you are curious, 0xC2 0xA0 is the two byte sequence in UTF-8 that represents the single character at U+00A0.
https://en.wikipedia.org/wiki/UTF-8 http://www.fileformat.info/info/unicode/char/00a0/index.htmAs @Alan-Kilborn said, the search-and-replace feature works with the actual character codepoints, hence uses \x{A0} or \x{00A0} to match that character, whereas the Hex Editor works with the individual bytes, so shows you both the byte 0xC2 and the byte 0xA0.
Like the hex editor, The MIME Tools plugin uses the raw bytes, rather than the characters. You can easily see this in my example, which using MIME Tools > URL Encode shows non%C2%A0breaking%C2%A0space, so you can see %C2 and %A0 are used to encode the bytes 0xC2 0xA0 which are used to encode the character at U+00A0.