"There are probably so few Dutch people who don't speak perfect English

that's its not worth bothering with :-) "

Well that is true the majority of Dutch/Flemish also know English well,
however... I have encountered people that do not understand some of the
finer 'qualities' of UK railways, so I have always learnt some people
at Harwich on what to do about where they're going and such as
sometimes... "change trains" / "overstappen" gets lost in the
translation, especially when originally they were told otherwise...
I wouldnt mind doing that for my life... helping the bewildered with my
dutch (simple as it may be, so far I can recall approximately 100
people (mostly in groups) over 4 years I've helped find where they want
to go... so its not bad for this unpaid 'helping hand'