Sci Fi London Film Festival

I'm thinking of going to the long weekend (Nov 9-12) this year, but haven't been before. Has anyone here gone, and knows enough what it is like so I can tell if it fits with my physical oddnesses? Is it like going to the cinema with an advanced ticket, just walk in - or do we need to stand in queues for more than about 20 minutes? Is it crowded and hard to negotiate if you're a bit fragile and need space to move? If it's spread out between multiple venues I'm fine with that - get a bit of a walk in between films :-)