Our chairman Gareth Edwards announced this morning that the speakers next year will be, God willing, Dale Ralph Davies and Gareth Williams (Bala), (Heresy Huntin') Martin Downes, Bill James and Stuart Olyott. Looks good.
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.