Waterslade in Redhill, Surrey, is in UK area code 01737, which is +44 1737 in international format.
(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.)
UK area code 01752 (or internationally +44 1752) is Plymouth.
01942 is the area code for Wigan and the surrounding area. Wigan is located in Greater Manchester, in the North West of England.
The 01628 area code is for Maidenhead, Berkshire, England, and the surrounding area.
The area code 0121 is in Birmingham.
01392
1524
Area code 0121649
It all depends on what area of England you want ! Each area has a different code, there is no code for England itself.There are many post codes in England, so it depends on where you are writing to. The post code is only one part of the address. You need to know it all.
Taunton
UK area code 01708 (a.k.a. +44 1708) is Romford.
There is no 021 area code in England. There is 020 (London) and 023 (Portsmouth and Southampton) but none in between!
Leyburn, Wensleydale