pogriallais,
Some of the advice those experts in the UK have given you is not appropriate for a startup.
1) $5 million would be nice, but it is not even remotely necessary to get a new distillery off the ground.
Planning for production of 50,000 cases per year from the start is crazy. You don't need to buy stills/fermenters on that scale in year one.
It is easy to buy additional stills, fermenters and boilers as your demand increases.
2) Once you have a product that is in demand, even on a small scale, then it is easy to find additional capital from investors.
If you start small and have a great product, then when you do need to sell equity to investors you will end up retaining a larger percentage of the company.
Right now all you have is a paper business plan. Selling equity now will result in you losing the largest percentage of the company.
You wrote that you have $400,000 to $500,000 in personal funds for this business. That is more than enough for a startup distillery.
We did our distillery for roughly that amount and it included construction of a 2,400 sq ft building that could have a tower for our 32 ft column.
My advice would be to start the company with only your personal funds and retain 100% of the equity for now.
Once you have production and a good product, put it out there for competitions and try to get some recognition that it is high quality and in demand.
If you really have something, then investors will be easy to find to fund expansion. And since you are already a proven product at that point, you will end up retaining a far larger percentage of the company.
Just my opinion.