South East London is around 5700 kilometres, or 3540 miles, from the Equator.
If you would like more information about how to calculate how far you are from the Equator, please see the following link:
City to Equator distance calculator from sciencing.com
A basic way to work it out is to take your latitude and to multiply this by 111.111. This will give you the answer in kilometres. To convert to miles, multiply by 0.621.
Please see below video explaining why the distance you are from the Equator affects the weather you experience.