Almost done. Arranagement of elements: potassium, nickel, iron and silver in part (5,5) _ S _ L _ / KNIFE. Can't get the "silver" part of the clue. TIA :)...
There seems to be a Nina in the 4th row: MORRISON. Too improbable to be anything else. But I can't see any follow-up or continuation elsewhere. The 14th row has "DUE CE ME" which makes sense...
14a). 21 (21d = fliers)against installing electronic warning light (6) _ E _ C _ N I assume the answer is BEACON. I can see BEE + CON..... but 4d). Musical's essential elemenr (7) S _ L _ C _ N I...
9a Warning over university restricting theological study (2,4) 6d Bedroom frolics set back? I suggest we should brood (10) 13d Curse big businessman, one installed in shop (10) Too few letters placed...
LOI, totally stumped. 5. Tobacco, when combined with fat, may be 9, 15 (5, 10). 9,15 is YELLOW SUBMARINE. I'm pretty confident in the crossers B_A_Y, _C_O_T_A_E. Possibly an anagram of...
LOI: "1,4 Previous message in a bottle (6,6).
Crossers P_L_C_ _E_O_D
I'd guess "Police Record" but can't see parsing. Second word could be "Second", first could be "Palace", but I can't parse....
Last one, totally stuck on 15,25a: "Driven thing with little power, sadly Blair not in control (7,5). I have crossers _e_i_n_ r_b_n, not certain about the r....