Here are some very nice blogs that are about, or frequently feature religious art and architecture, and are probably much more sensible than mine:
Church Architecture: Sacred Buildings in the Modern World (Irina Ghiuzan)
Echoes of the Past (blosslyn)
Heartchitecture (Ayla Lepine)
Inscrutable Being (Evan McWilliams)
Medieval Church Art (Allan Barton)
medievalwallpaintings (Ellie Pridgeon)
Via Lucis (Dennis Aubrey)
Here are some useful resources for churches, London and beyond:
Stained Glass Records – This is what I use to attribute all the stained glass windows on my Flickr uploads. Amazing coverage for all of London, and counties to the south, west and north of it.
British History Online – For the Victoria County History and Royal Commission of Historical Monuments – often as good as Pevsner (if not as comprehensive coverage): completely free! Other sources too.
The Taxatio Database – See how much your parish was worth in 1291!
And here are some other blogs I’ve helped out on or written a guest post for that may be of interest: