The Italian, British, French and Iberian Late Neolithic groups are unified through a common dominance of i2a1-m223, which is however a seperate clade from the I2a1 of the preceeding, and ancestral to all of these, Cardial Culture (I2a1-l161, the same as Funnelbeaker).

There are many things that could have happened here, such as individual founder effects or contributions from local hunter gatherers. Singleing out exactly happened would only be possible through high-coverage IBD connections.