Where in the UK is area code 020 847?

UK telephone area code 020 is London. A number beginning with 020 8401 could be located anywhere within the greater London 020 area, including both the former "inner London" and "outer London" zones. No more detailed geographic information is possible.

(The plus sign means "insert your international access prefix here." From a GSM mobile phone, you can enter the number in full international format, starting with the plus sign. The most common prefix is 00, but North America (USA, Canada, etc.) uses 011, Japan uses 010, Australia uses 0011, and many other countries use different prefixes.)