Clive pretended :
I'm completely flabbergasted at the price being asked for sheds that
seem to me to be made out of match wood.

Is there a good book that shows clearly how to build a simple wooden
shed out of 2x2 timber and wooden tongue and groove cladding?

Why should you need one?

Just go along to a showroom and look at how their huts are constructed,
make a few notes, take a few digi photos. Then decide what layout you
need and get on with it.


Would one of those "sliding" rotary saws be a good tool to cut the
timber?

Yes.
I'm looking for an excuse to buy one

Where could I buy simple fixed windows to fit into said structure? I'm
only interested in getting a little light into the gloom, not
fantastic ventilation.

You do not need to buy a window, just the glass. Just make a frame out
of 2x2 then add some 1/2 x 1/2 fixed along the inside of the 2x2 frame
to sit the glass against. More 1/2x 1/2 to retain the glass on the
outside.

--
Regards,
Harry (M1BYT) (L)
http://www.ukradioamateur.co.uk