481914-11111918 by Gnomie

The theme was a 42ac of 2d (5,8 of 1,1,1). The title applied to the clues will guide solvers with regard to what to highlight in the completed grid. One solution is in the ODE, not in Chambers.

    1    Dreadful waste for common soldier (5)
    5    Religious recluse's ill-made trench coat, trimmed at both ends (8)
    11    Transliterated from Greek, this comes at end of open hostility (3)
    14    Fire-watching absorbs this old unit (3)
    15    Original fatalities (men) in last approximate calculation (13, 2 words)
    16    A mark, shot from regularly in anti-tank war (3)
    18    Here, thematic character distinguished himself when securing damaged mine (6)
    20    Involving people on the inside sheltering according to staff officer (13)
    23    Storehouses preposterously separate; Royal Artillery excluded (6)
    26    Whisky's staple takes us out of hell and back (4)
    27    Originally how fighters must assimilate IT, having ability to predict what will happen (13, 2 words)
    30    Disintegration of a trial producing bright gaseous mass (6)
    32    Dutiful thematic character if stirred up could give woe and pain (3)
    34    Notes position after retreat (3)
    36    Reactionary evil smear (3)
    38    Disheartened, try pity, from time to time, with new very small foreign unit (5)
    40    In a tumult initially losing nerve and denying ceaselessly (13)
    42    See preamble (13, 2 words)
    47    Harsh long-continued struggle backfiring (3)
    48    General situation's limitlessly irreconcilable (3)
    49    Scenes of lively action surrounding first of operational sudden short attacks (6)
    50    Weapons led astray, with troubled thematic character absent, passed into disuse (6)
    1    It rises, surrounded by warring foes for a weak person (6)
    2    See preamble (3)
    3    One exceptionally long period (3)
    4    Haplessly each pal advanced becoming class of dangerous creatures (8)
    6    Distraught prisoner endlessly more offensively curious (6)
    7    React chaotically to provide rations (5)
    8    Units in the employ of the King? (4)
    9    A-list once occasionally elevated such beings (5)
    10    Without orderly aide, deliberate about the highest part (6)
    12    Scottish rogues; male politicians (5)
    13    Dying, shelled, in principle associated with earth, dark and cold (3)
    17    Opposed to violent action, company leaving (4)
    19    Unexcited night before main event for thematic character, possibly (3)
    21    Replacement of equipment burnt ultimately after wild fire (5)
    22    Funeral ceremonies with no time for exotic religious belief (3)
    24    Miserably pitied, lacking independence and with little enthusiasm (5)
    25    Unit's occasionally past it (3)
    27    All the thematic character can do in armed conflict situation finally (4)
    28    Thematic character, OTT, swallowing this old rye could become noteworthy (3)
    29    State of horror when top blown off explosive projectile (4)
    31    Letter turns up in bits of veteran's army tackle (3)
    33    Record article on advance in northern lines (5)
    35    Respectful form of address for example with less than half of language (6)
    37    Fine French auberge more than half destroyed (4)
    38    Irritable fellow employed to care for mechanical equipment, maybe (5)
    39    Plants offensive to the sight, we hear; weeds finally (5)
    41    Indian barbers regularly inhabit lowest bit of dugouts (4)
    42    Young collectively in battle; adult absent (3)
    43    Anything locally served up for what is said to be company (3)
    44    Unit permitted absence from duty (three-fifths only!) (3)
    45    Note of defeat mostly recollected (3)
    46    Fruit's terrific, it's said, with 29 removed (3)
To enter this competition, send your entry as an image or in list format with an explanation of the highlighting, to ccpuzzles@talktalk.net before 8th December 2018. The first correct entry drawn from the hat will receive a book donated by  Chambers.