[QUOTE=Solanum
I'd also be interested on any thoughts on whether this fireball was random or connected with a metor shower (bit late for the Leonids I imagine). [/QUOTE]
Just getting around to answering all your questions, re wether it was associated with a meteor shower, extrapolating it back to N/E in origin, using your report and excellent photo, I see their is a slight possiblity that it was a late Taurid - this from
http://en.wikipedia.org/wiki/Northern_Taurids
'If large enough, these meteors may become bolides, with spectacular light shows and even audible sound.'
'The Taurids are also made up of weightier material, pebbles instead of dust grains.'
seeing the radiant was just above the horizon for you at that time, these are the most likliest to be the source if it belonged to a shower.
There is also a chance it was an early Geminid, they also can produce spectacular fireballs, but the radiant was waaay below the horizon at the time, so it would be unlikely.
but doesnt have to have pedigree to be a nice meteor, could of just as easily been a sporadic random event.
HTH