Keep the bloody thing Chas, and spend it on beer, or marshmallows, or a gimp suit, or whatever makes you happy. There’s no need to agonise over it … it’s only a bloody fiver. I’d take as many tips as I could get if I was back on home deliveries.
Why not donate it to http://www.mind.org.uk where it will be put to good use helping other paranoid schizophrenics?