See http://yba.llgc.org.uk/en/s-LLOY-RIC-1834.html on the influence of Richard on David Lloyd George.  The correlation between the US Disciples and the Welsh Disciples is not necessarily causative although the Americans were certainly aware of their British counterparts and supported them. See Restoration_Movement#Great_Britain. Thomas Campbell (clergyman) and Alexander Campbell (clergyman) had already acquired their religious mind set in Scotland before leaving for America.