Christian McArdle wrote:

so I guess it will either need to be up above head height,

Above head height is what I was thinking. Remember, modern condensing dryers
are actually quite good. You don't need a huge amount of ventilation, just
enough to clear the air eventually. Nothing like the massive amount of
ventilation required for a vented dryer.

Just opening the door for an hour or two would also work, but might not be
to your taste.

I'd actually wondered if I could get away with just fitting a vent to
the cupboard door so that the hot air could vent gradually to the
hall...

Thanks again for the info!

Cheers

Helen