I can thoroughly recommend a visit to Bristol City Museum to view the Banksy Exhibition.
There is no objection to photography providing you don't use flash
However, in several locations the lighting is poor and although using 1600 ISO (which is the highest I can use on my EOS 400D) I was shooting handheld at 1/30th at f3.5.
The biggest problem is the queues
I was there at 9.15 and went in at 10.10, but when I came out at 12.00 noon, the queue was back to the '3 hour wait' sign.