Literary festivals profile literary fiction in the main (as opposed to ‘genre fiction’). Occasionally, you’ll get a kids author, a crime author, even the very occasional fantasy author attending, but it’s usually dominated by celebs-turned-author, ex-politicians and those who pen litfic. Still, if that’s your bag, then you’ll be interested in the following list of the biggest ones…
Edinburgh International Book Festival, 9-25 Aug 2014: https://www.edbookfest.co.uk/: the big one!
Hay-on-Wye Literary Festival, 22 May-1 June 2014: http://www.hayfestival.com/: Hay-on-Wye has more book shops per head of population than anywhere else in the UK: this festival is a pilgrimmage for many
London Literature Festival, May-June: http://www.southbankcentre.co.uk/whatson/festivals-series/london-literature-festival: one of many lit festivals that take place in London: others include Richmond, Stoke Newington and Soho
AyeWrite Fesitval, Glasgow’s Book Festival, mainly in spring: http://www.ayewrite.com/
Bath Literature Festival, March: http://bathfestivals.org.uk/literature/: an independent festival, but attracted JK Rowling in 2013
Nottingham Festival of Words, Feb probably 2014: http://nottwords.org.uk/: no info available yet
Cambridge Wordfest, twice a year, winter and spring: http://www.cambridgewordfest.co.uk/: well organised, clear info, a committed festival team
Manchester Literature Festival, throughout Oct 2013: http://www.manchesterliteraturefestival.co.uk/: well resourced and running since 2006, it attracts international names
Ilkley Literature Festival, 4-20 Oct 2013: http://www.ilkleyliteraturefestival.org.uk/: extremely well established and long running festival
Cheltenham Literature Festival, 4-13 Oct 2013: http://www.cheltenhamfestivals.com/literature: a comedian, a musician, a matter of taste
Birmingham Literature Festival, 3-12 Oct 2013: http://www.birminghamliteraturefestival.org/: well resourced and attracting big literary names
And there are many more, of course. If you desperately want your own added to the list, just scream.
Metaphysical Fantasy 
The big festivals are jumped up author tours; I’ve been to Hay-on-Wye and to Manchester in pre-writing days. Locally there’s been nothing until 2016 which was Burnley’s first. We had a mix of local authors ‘coming out’ (Burnley hasn’t had a bookshop for at least a decade) and out-of-town treats —from places like Manchester (Burnley folk are insular so Mancunians are definitely ‘out-of-town’).
The Sufi music was interesting – something I’ve had an on/off interest in for 30 years +. Having said that, the festival prompted a YA novel from me.