'Outside' as in (potentially) stopping an employee from working for another company whilst employed with them.
DD is looking to do bank work with a carehome. As there are unlikely to be enough shifts she was hoping to also do bank work with another provider, however the contract of employment says she can't unless she gets the company's express written agreement. She'll also have to advise the company if she works >48 hours a week.
I thought such restrictive practices had been got rid of?