The message
from Stuart Noble contains these words:

You could glue one of those soft close dampers to the extractor. Quite
small and unobtrusive. B&Q do them as an extra for their kitchens but I
don't know if they're available instore.

They are - I bought a pack of five for £6 the other day. Bliss - the
kids don't slam the cupboard doors any more. Well, they do but the
dampers work.

You can get limited opening hinges.

--
Skipweasel
Pay no attention to that man behind the curtain.