First, based on the updated scientific advice, the Government is advising that if you or anyone in your home has a high temperature or a new and continuous cough, then you should stay at home for 7 days. If you share your household you and others within it should stay at home for 14 days. This is to ensure that if others within the household catch the virus they are kept isolated to prevent infection spreading further.
If at all possible, you should not go out to buy food and essentials.
Instead you should ask others for assistance with your daily necessities.
The exception to this is for exercise. Even then, you should keep at a safe distance from others.
If it’s not possible to receive deliveries at home, then you should do what you can to limit your social contact when you leave the house to get supplies.