I've just published a chapter in the following book: Mark Smith (ed.), British Evangelical Identities Past and Present: Aspects of the History and Sociology of Evangelicalism in Britain and Ireland (Milton Keynes: Authentic Media, 2009). My chapter, entitled 'Methodism and the Origins of Evangelical in Wales, 1735-62', attempts to account for the beginnings of evangelicalism in Wales in the mid eighteenth century. It tries to argue against those who tend to interpret the Welsh Methodist Revival in more evolutionary terms, stressing its discontinutity with previous expressions of Protestantism in Wales and its place in the emerging evangelical movement in the mid eighteenth century British Atlantic world.
There's lots of other really useful stuff in the book too, including much on contemprary British evangelicalism. Available from: http://www.authenticmedia.co.uk/AuthenticSite/product/9781842273906.htm.