I'm starting my own brewery and I'm stuck with what to add to my business plan that I might've missed

I've done a full financial plan for the next 3 years, the business model on how I'm going to sell and produce it has been done. I've talked about: marketing costs, packaging, rent of property/ equipment (I'll own the equipment but rejt it out to the brewery from a separate business), insurances, tax (including the alcohol duty to pay) wages and delivery costs. I've made those costs higher than they will be to account for potential changes in prices.

It's only 4 pages long and I've been told that it should be at least 10-15 pages but I'm unsure about what I've missed. If anyone had any ideas of things I would appreciate the advice.

Edit: Thank you everyone for all the comments. They've been a massive help so far. Got loads to think about