London Divisional Leagues (levels 5-9)

A pyramid of Five 'Divisional' leagues, with level 5 - National Division 3 London at the head. 
Despite its title, Sussex Division 1 is, confusingly, a London Divisional League

National Division 3 London (Level 5) comprises Clubs from Eastern Counties, Essex, Hampshire, Hertfordshire, Kent, Middlesex, Surrey and Sussex.

The four CB's (Counties) South of the Thames, (Kent, Middlesex, Surrey,Sussex)  form 'London 1 South' (level 6) 

The next level normally pairs Kent/Sussex and Surrey/Hampshire form London 2 and 3  South East and South West,
at Levels 7 and 8 but to avoid excessive travel, and to balance the effects of Promotion/relegation, some Clubs eg Bognor or O. Reigatian, are moved over the other pair, under a system called 'level transfer'

The 8 CB's (Counties) have their own pyramid, headed by their County Division 1 League (Level 9)
At present, Sussex 'Spitfire' 1 is the only CB to include 'lower' - i.e. not First XV's in their County 1 League.   

Fixtures for London & S.E. Divisional Leagues  appear on the RFU London website and the RFU website

'Divisional Leagues' for National 3 London - London III SE, and 'Sussex' ('The Counties' ) for Sussex Spitfire 1

Select 'London & South East Division' and then a League