A very elementary question which most of you wouldn't have to think twice
about, but...

My cooker hood has just today finally packed up and 'joined the choir
invisibile'. It's an absolutely basic type and quite ugly but it is vented to
the outside and actually worked quite well.
(Photo here if it helps: http://gallery.me.com/mike_lane#100262)

My question is how difficult would it be to replace it myself with (say) one
of these:
http://www.johnlewis.com/230448800/Product.aspx
or something similar? The electrics are no problem - the old one simply plugs
into a 13A socket on the wall above the unit. The dimensions are almost the
same, but what worries me is how it fits onto the outlet pipe - I know
absolutely sod all about tubing, pipes, ducts and all that sort of thing.
Pathetic I know, but there it is.

I'd be immensely grateful for any (practical) advice - thanks.

--
Mike Lane
UK North Yorkshire
mike_lane at mac dot com