Plot: Suzy Klein introduces a richly colourful Prom programme from the BBC National Orchestra of Wales under the charismatic young French conductor Francois-Xavier Roth, ranging from the scintillating French Baroque of Rameau to new music by the Argentinian composer Matalon, via Canteloube's evergreen arrangements of Songs of the Auvergne. The programme culminates in Mussorgsky's famous Pictures at an Exhibition, in an extravagant orchestration by Proms founder Sir Henry Wood himself