Rhodri is doing another play soon (Flowers of the dead red sea by Ed "Hinterland" Thomas). He has been interviewed briefly recently (with producer Izzy Raby). If you have Welsh you can hear it here. Also check here and here.
Bonhoeffer uses a similar phrase 'worldly Christianity'. It's J Gresham Machen that I want to line up most closely with. See his Christianity and culture here. Having done commentaries on Proverbs (Heavenly Wisdom) and Song of Songs (Heavenly Love), a matching title for Ecclesiastes would be Heavenly Worldliness. For my stance on worldliness, see 3 posts here.