Many thanks to those who have responded.
I converted the mysql collation to utf8 general, added the meta http-equiv content to charset urf-8 and placed the code
if (preg_match('/^[A-Za-z\x{00C1}\x{00C8}\x{00C9}\x{00CA}\x{00E1}\x{00E8}\x{00E9}\x{00EA} \'.-]{2,40}$/u',$trimmed['last_name']))
This worked and accepted the match. So far so good.
But when I looked at the mysql db, the word Carré had been stored as CarrĀ©
Where did that come from?