HI Dutto,
Agreed, at the offset it seems a massive challenge, but let me share what I have done so far.
Yeast washing (removing the need to buy and for providers to manufacture or ship it).
I solely use Westminster organic Malt, which according to there web page is UK, I also buy it in bulk to cut down trips and travel. This add up to less chemical and less shipping.
I also grow my own hops and I'm lucky enough to live near a belt of old hop gardens and they grow wild here. Its fun from time to time to roll the dice and use the wild hops.
I keep chickens and all my old grain is used for feed and the chicken poo is used to fertilize the hops.
I use insulated hot liqueur tones and I try to buy equipment with a long life, both have an impact on energy used.
I recycle as much of the water as I can either for cleaning for watering the garden.
Not driving to the shops to buy beer, not recycling cans and glass.
Lots of these things most people here are probably doing anyway and they all add up. Most brewers probably just not putting being sustainable as much as you can at the top of what they do.
thanks L