Thanks Malone. Got three corners sorted now, but unsure of top LH corner.
1a) Wondered if VICTS is to dispense with for 1ac?
2d) I have - - TI - H -, but if my guess at 1ac is right, the first letter will be N, suggesting Nona for soon backwards. But church music?
3d) Still foxed on the mineral. It ends ELITE, but the only candidates I can think of (nephelite, scheelite) fit neither the clue nor the theme.
11a) A - - -
A pointer towards any of these might inspire me for the others.
Right now - stumped!