Hi everyone!
Since I was looking for some time to find a good child seat for the Brompton G-line, I just wanted to let you all know that I found a good solution in the Tyketoter (https://www.tyketoter.com/). Not as sturdy as the Pere seat for regular Bromptons, but works great for my smallish 3-year-old (around 15kg).
Have a nice day!
by Swimming-Site9318