In the last 2 months, I've seen 2 refs suffer duff whistles. One was in an Ospreys game on TV and the other was in my boys District game. In both cases, the refs just reached into their pocket and pulled out a spare.
I'm not sure if he was winding you up Mr Whittaker. When I did my WRU Level 1 course, the ref in charge told us that good refs were expected to be able to play a tune on their whistle, to adjust the tone during the game. Sadly, he didn't tell us how to adjust the tone.
In fact all my whistle blowing sounds monotonous (only the volume changes) and I was thinking of starting a thread on how to get it right. The only reason I haven't, was because it may appear such a stupid question - and I've already exceeded my quota of stupid questions for this month.