Easy to miss if you're coming from the cathedral as it's around a corner that will put it at your back so tread carefully. It's worth any extra effort it takes to find it.
Hint: It's across the street from The Salvation Army building which is well signed and easy to spot.
One of the best historical displays we've seen anywhere. Plenty of detail for the serious historian but done in such a way that the accompanying casual visitor isn't overwhelmed. Staff is wonderfully helpful - explained carefully how to use the interactive exhibits.
It features the actual foundations of an ancient "long house", uncovered during the excavation for a new hotel that is now complete immediately above it. Yes, the museum is effectively in the hotel basement.
Only reason I didn't call it excellent was that one of the major inactive displays was being repaired though a crew was very busy puzzling through making it right.
Children marginally likely to enjoy so their absence perhaps enhanced the ability of adults to enjoy everything.