Who were the early London Baptists?

According to the Baptist Union Directory, organised Baptist life in England had two distinct beginnings:-

• General Baptists: In 1611, Thomas Helwys led a small group back from Holland - a few years earlier they had sought freedom there from religious persecution. The Helwys group initially established themselves in Spitalfields, London. But Thomas Helwys was soon arrested and put in Newgate Prison where he died before 1616. The successors of Thomas Helwys and friends became known as General Baptists. By 1618 the Spitalfields church had moved to Crosby House; in 1625 Elias Tookey led a small group away to meet in Southwark (on the south of the Thames). By 1639 there was one General Baptist church meeting in North Folgate, London led by Thomas Lambe, and another meeting in Bell Alley, London led by Edward Barber.
• Particular Baptists: In 1633, a group split away from a Calvinist Separatist church in London on adopting believers' baptism and by 1638 were being led by Samuel Eaton. Another group split away from the same original Calvinist Separatist church in 1638, this time led by John Spilsbury. The successors of these two groups became known as Particular Baptists.

If you have a particular interest, try enquiring further through the Baptist Union or Regents Park College, Oxford. There is also Baptist Historical Society (c/o Treasurer, Baptist Historical Society (c/o Rev T H S Elwyn, Treasurer, Baptist Historical Society, 28 Dowthorpe Hill, Earls Barton, Northampton NN6 0PB, UK) which has published detailed books on Baptist history like "The English Baptists of the Seventeenth Century" by B R White (1983). A simpler summary is provided by "English Baptist History and Heritage" (published 1990 by the Baptist Union as part of their Christian Training Programme).