It can turn over a billion pounds, but the figure you need to look at is net profit.
If you buy a company, you buy its debts (remember MFI being sold for £1?) as well as the assets - and only thorough due diligence will give you a reasonably full picture.
Companies are often evaluated on assets and cash flow. When you say does the company turn over £1,000,000 a year is that gross sales, gross profit, net profit?
A company is worth it's net assets plus goodwill
It depends on how much the stock is worth.
The business itself may not have much value, unless it is a well known brand.
If you were going to buy a company that turns over a £1,000,000 a year including all stock but not the building as it will be rented, how much would that company sell for ?