@ThankYouVeryMuchGerry Hard to say without knowing what you like, but Maison Margiela By the Fireplace would make a great autumn scent. It's a smooth smoky wood, with a touch of sweetness and vanilla. So cosy! I, personally, don't find it heavy and most people seem to like it. An easy way to sample this is through the feelunique pick and mix selection which gets you 5 samples for £3.95 postage (I think).
Guerlain Mitsouko is also quite autumnal, it's a fruity chypre, with a bergamot/floral top, peach (LOTS of peach) and incense in the middle, and a mossy warm base. If you like summery scents, then the peach in this makes me think you may like it. Also, Guerlain Samsara is jasmine and sandalwood, but spray lightly if you don't want something overpowering.
How are you with incense? If you like incense-y scents, something like Comme des Garcons Incense Avignon or Heeley Cardinal.
For Tom Ford, maybe Tobacco Vanille? Might be warming for autumn without being heavy or cloying.
Green scents can be quite autumnal too, maybe Estée Lauder Private Collection or Chanel No19. Clinique Aromatics Elixir is definitely a wintry chypre to me, but can be quite strong.
I actually love orientals and Ambers for A/W (or any time really!), so don't have many suggestions, but I'm sure someone with more knowledge will be along with more suitable ideas. 