We have purchased a small piece of land in an industrial area of town. The only other food merchants are food trucks that come around with sausage sandwiches and other basic street food you'd find in the UK.
You already have part of your answer. You know what types of foods the local workers are eating based on the food trucks.
What you need to consider is how much of that type of food can you sell and at what cost in order to recoup your costs to develop the land.
This is assuming that there are currently no buildings on the land that can be converted into a restaurant.
Keep in mind that you are in an industrial area, how many shifts are there, how many workers buy their meals, and not bring them from home.
The first step I is to find out the cost of development, while doing that make a survey and go down by those food trucks (if you can afford it hire some young people to do that for you) Count the number of customers that eat there and ask the people that buy food there if they would come to a restaurant if it was built? What kinds of food they would be looking for? How much of a break do they get for meals? Things of that nature.
You may find it better to develop the land in an industrial way rather than a restaurant. The surveys will reveal the possible amount of customers you potentially have, and can give you a price point on how much they are willing to pay, and even do they have the time to come to a restaurant to eat.
What is the daytime working population of the area you'll open up in? Most of your clientele will be people who work or live very close by.
I'd start by identifying the size of the market near you and then estimating how many of those people will choose you over your competitors. If you're offering something totally new and different for this area and demand is high, you shouldn't have much trouble getting people through your door.
With regards to your cost analysis - with any food business, the cost of food is typically about 30-33% of the price you sell it for. Staff often add another 30% and operational expenses, another 30%. You can use this benchmark to set your pricing and then monitor and evaluate as you go.
I have years of experience working with food start-ups on business plans, financials and market research and would be happy to have a call with you.