We went to collect my son from Bristol just before Christmas and made good time on the journey, in fact with time to spare.
Bristol is a fascinating city with many old buildings blending in reasonabley well with the modern, it's harbour and just the general atmosphere a being alive and well, thriving in fact. Faced with an hour or two burn it wasn't difficult to think of a good number of places to visit; in the end we went for SS Great Britain.
SS Great Britain was designed by brunel and was launched at Bristol in 1843. It is one of the most important historic ships in the world being the first steamship built of iron and also the first ocean going ship to be driven by a propeller and not paddles. More information is on their website.