Non specific service joke which you might be able to adapt, as told live on Capital Radio by DJ (and ex Stoker) Mike Osmond.
'Coming to work at Leicester Square at 5.00am yesterday morning, pitch black, cold and raining. A beggar is on the pavement outside the entrance to Capital Radio, sat on his piece of damp cardboard, only got one arm, begging bowl out in front of him and a sign which reads "I lost my arm in the South Atlantic serving my country in 1982." I thought, poor chap, put my hand in my pocket and deposited a crisp 20 pound note into his begging bowl. With tears in his eyes, the ex serviceman picks up the twenty pound note and gives me a heartfelt
"Muchos Gracios Senor"
