A very useful site, where you can read back copies of many different poetry magazines online, is
http://www.poetrymagazines.org.uk/
Other magazines I've had success with are
Obsessed with Pipework ("off-beat" poems - have a look at their back copies on the site just mentioned) and Raw Edge (Midlands based, a good starting point for submissions.
http://www.poetrysociety.org.uk/landmark/display.php?id=876 )