I've read all of Wesley's writings and cannot find much evidence that he consciously drew upon ancient Celtic Christian materials. A number of those themes, such as small groups, hospitality and imagination, were by that time in the DNA or ancestral memory of British Christianity. From time to time, various movements in the Christian community have rediscovered and reinserted those themes. The current Alpha course is a more recent case of a movement reappropriating many Celtic Christian outreach principles without being fully aware of their ancient source. You spent time in Ireland, Scotland, and England at places like Ionawhile preparing your book.
Many people seem to be doing that.
I think that Celtic Christianity virtually invented the pilgrimage, and our generation has rediscovered its subtle power. We experience, in ways we cannot fully explain, that we are more likely to experience God at Iona, or Lindisfarne, or Glendalough, than in downtown Manhattan.