Phoenix Mag.

[fuzzy-brain]

13a: Will it be organically broken down in oily sediment? (5). L _ I _ _ (I think).
7d: Just imagine what England's leaders face! (8). H _ S _ _ _ G _ . I've put 'Hustings' but I don't think it's right>
8d: To a greater degree, women suffer from different diseases. (8). _ _ L _ _ _ E _. I'm not certain that the letters I have are correct.
Any help greatly appreciated.

[Lie-in King]

13a "...oi LY SED iment" - from 'lysis' - breaking down, eg of a cell
7d Envisage (imagine) - En(gland's [leaders]) + visage (face) (?)
8d Maladies - M(aster) [of] A(rts) (degree) + ladies (?)

[fuzzy-brain]

Very many thanks for that, Lie-in King!