In was at The Heart Hospital yesterday and they seem quite happy with progress made. My Sabbatical leave officially started last Lord's Day and so I have spent the week reading and writing. I have various projects on hand including a little local church history and a book for pastors as well as further research on 19th Century Baptists, the period 1660-1689, etc, etc. I've mad a good start and hope I can keep it up.
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.