If you would like to see how a competitor company did for the last year, you can go to companies house and download a copy of their accounts. Unfortunately, the accounts at companies house are not the full accounts showing a detailed profit and loss and detailed balance sheet, but are an abbreviated set. If the company is small, all it is required to file at companies House is an abbreviated balance sheet and a few notes to the accounts. A medium sized company is required to show a profit and loss account and a balance sheet. However, for a medium company, the profit and loss it files is not very detailed.
To find company details go to Companies House beta and search for the company you want to research: