Mackay ........ I do a version of this and the second time round miss out the word UP

The Grand old Duke of York he had 10,000 men
he marched them ... to the top and the hill
and he marched them down again
and when they were ... they were ...
and when they were down they were down
and when they were only half way .. they were neither .. nor down

then the next round miss out down instead, and finally miss out up AND down

The grand old Duke of York he had 10000 men
he march them .. to the top of the hill
and he marched them ...again
and when they were ... they were ...
and when they were ... they were ...
and when they were only half way ... they were neither .. nor ...

If you eliminate people for singing the up or down words when they shouldn't you'll probably find your the only person left standing (unless of course you cock it up !)