Cryptic crossword No 3,149

Did your crossword there, some great clues! Liked 12A, 15A, 19A, 22A, 23D. Some feedback: 9A: I think flat -> 0 volts -> ov is too much of a stretch, it's not really a commonly used abbreviation. 3D hiddens shouldn't touch the edges! (the fodder is THEMEMORY and the T is out in the open there. You need at least one letter before the T. 24D "Wells" doesn't do anything and should be removed. I also think that the def should be the singular form "African". Thanks for the puzzle, though