Police say the attack was part of a feud between two rival groups in Essex.
All three men are due to appear at Norwich Magistrates' Court on 10 July.
Reform UK's election campaign raised the prospect of Havering leaving Greater London - a position their local leader now disowns.
Trading Standards officers say the network operated in Surrey, London and Essex.
BBC London speaks to voters in Romford and Dalston about what they want from their new councils.
The 15-year-old was charged with the murder of Eghosa Ogbebor who was fatally shot in Woolwich.
The adverts feature Andrew Rosindell, the local MP who defected from the Tories to Reform UK.
Havering has done things rather differently, but the issues here might sway voters across London.
A boy appears at the Old Bailey charged with the murder of 14-year-old Eghosa Ogbebor in Woolwich.
