High street shops are generally open 9 am to 5.30 am, Mon - Sat. Some shops possibly close an hour earlier on a Saturday. Banks are slightly different, usually 9 am - 4.30 pm Mon - Thu and normally close an hour earlier on Fridays. Some, not all, will open till noon on Saturdays.
Supermarkets rarely close before 9 pm, 11 pm is not uncommon and in big cities you will find several 24-hour supermarkets.
Sundays are not always so simple, but you will never be far from somewhere to buy groceries. All suburb areas will have grocery stores open until 8 - 10 pm. Large towns may have some stores open, while in big cities there will be little difference to any other weekday.
Despite England´s renowned 11 pm drink curfew, this is rapidly becoming a thing of the past. Bars generally open at 11 am. Very few close in the afternoon, and its not difficult to find somewhere (apart from nightclubs) to enjoy a drink until 1 - 2 am.
All banks and most high street shops will be closed for Bank Holidays, but supermarkets normally remain open.