Interesting idea.. i cant really help you though, id rather nick the list off you once you're finished! To be honest you'd be better off talking on forums where people know more about the music industry.. try somewhere like Ninehertz. also ask labels (labels which are a little bigger than me!) and Rocksound magazine may be able to help.
british
PR companies i have dealt with are S-a-N Agency, Division and Hero
PR, though if you've odne any research you'll probs know them already.
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Out soon...
AMENRA - Mass III 2xLP [stunning vinyl release of the belgian sludgecore giants epic 06 album]
FALL OF EFRAFA - Owsla & Elil CD&LP [British crust/doom/post-metal band Fall of Efrafa deliver part two (Elil) on their dark conceptual trilogy. Part one (Owsla) will also be re-released for the first time in the UK]
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visit...
Sound Devastation Records website