I'm off to Prague next week. Are there any decent gunshops in the city or shooting & hunting orientated attractions?

Andrew,

go to the CZ factory gunstore, at Opletalova 6, close to Vaclavske nam. (Wenzel's square, very central).

You also might do a day trip to Konopiste, Archduke Fanz Ferdinand's hunting castle (major tourist attraction, expensive).
There is very good shotgun range (sporting clays) nearby.

I can really recommend a visit to the hunting and forestry museum Ohrada, close to Ceske Budejovice. But this is some 2 hours away from Prague.

Regards,
Martin