Answer:

cheerio

AnswerCrossword Clue
CHEERIOLondon farewell!
CHEERIOToodle-oo
CHEERIOSouthampton so long
CHEERIO"Ta ta!"
CHEERIOSoho "So long!"
CHEERIOLeeds leave-taking
CHEERIO"Ta-ta!"
CHEERIOLondoner's "Bye!"
CHEERIOBritish toast
CHEERIOBrit's "Bye!"
CHEERIOBrit's bye-bye
CHEERIO"Toodle-oo!"
CHEERIODefunct radio program.
CHEERIOSo long!
CHEERIOLondoner's greeting.
CHEERIOSalutation in London.
CHEERIOPiccadilly greeting.
CHEERIOPiccadilly farewell.
CHEERIOLondon greeting.
CHEERIOSo-long in Soho
CHEERIORelative of hello
CHEERIO"Ta-ta"
CHEERIO"Toodle-oo"
CHEERIOEnglish toast
CHEERIOBrit's goodbye
CHEERIO'Ta-ta!'
CHEERIOBritish farewell
CHEERIOSheffield farewell