It Takes Two (or More) by Atlas

Ten thematic clues contain a mixture of letters comprising the solution, without definition. In eight Across and eight Down clues there is a superfluous letter either in the definition or yielded by the wordplay; in clue order these letters disclose the theme. Remaining clues are normal. 

    1    'Arty' slur can be hurtful (8)
    7    Bombastic orator (5)
    12    Bellow when row follows start of race (4)
    13    Danced with lawless lot in Virginia (5)
    14    Cross when beloved one in Ayr gets more aged (4)
    15    Provoke anger protecting violent trait (8)
    16    Little and active prince put in nappy (6)
    20    Morning Glory starts impressively, peters out miserably after one effete attempt (7)
    21    Thug (it's appalling) throttling old fool (6)
    23    Argue possible form of gene holds key (6)
    25    At fault, as no team scorer (7)
    27    Press Dr Michael to overprescribe (9)
    29    Chasing you, my impossible dream (9)
    33    Disregard too much experience (7)
    34    Under shelter after gala, Briton shuns people of fashion (6, two words)
    35    Grass one found in dirt (6)
    38    In addition, English back group manoeuvre on ice (7, two words)
    42    Recess in carved end-unit (6)
    43    Lax Cyrus escapes miraculously; in trouble after - hard cheese! (8)
    44    Planet formed from selenium with embedded silver (4)
    45    Unused vinegar is feeding fish (5)
    46    Satellite leaves Earth rotating less - tense! (4)
    47    Classy little roadster (5)
    48    Your spade hit my foot (8)
    1    Parasitic relations infuriate (7)
    2    Swiss flower has a red centre (4)
    3    Scold Frenchmen obstructing tribe, right? (7)
    4    Nothing in casual workmate's possession leads to charge (4)
    5    Get bullets ready regularly for extremist (5)
    6    Armour-plated beast gets back, pours a cocktail (9)
    7    Rebel confronting Troy's younger son (5)
    8    Met again concerning fool with symbolic device (not last MD) (11)
    9    In India, grovel to priest and earl (4)
    10    Threatening characters locate me in the middle of Stonor Square (5)
    11    Some Viagra is going astray (7)
    17    Slope disapprovingly away without providing fresh input (5)
    18    Agnostic once discomfited those who claim to know (11)
    19    Bread put back in dormitory (4)
    22    Small fry without number stand around (4)
    24    State of head the result of drug smuggled into fish and chip production (9)
    26    Sot let it be stuffed into steam engine (4)
    28    Take in one making comeback needing bit of luck to make record (5)
    29    Exploit his possibilities (7)
    30    Old tinker perpetrates parking swindle (4)
    31    Artist's name is mud, losing title of respect for all men (7)
    32    Uppish aim misses target (7)
    36    Obsessive about number in year's entry (5)
    37    Rumours I put about, following Kelvin (5)
    38    Loop the tops from the god's headdresses in front (5)
    39    King leaving local lively becomes intense (4)
    40    Insect flew, but not with acceleration (4)
    41    Henry in science-fiction play reveals wartime target (4)
To enter this competition, send your entry as an image or in list format, to before the 8th March 2013. The first correct entry drawn from the hat will receive a copy of one of the range of books which has been donated by Chambers.