RPO/Calcraft, Royal Festival Hall, London

Better late than never, Exeter's centenary tribute to the late Joaquin Rodrigo staggered into town at the end of what would have been his 101st year. The composer of Concierto de Aranjuez is an enigma for many reasons. Almost everything else he wrote – despite blindness, he was prolific – is ignored. Popular in fascist Spain, he was showered with honours by the subsequent liberal regime; yet he wasn't a political animal. He was driven by musical craft and tradition, in many ways a forerunner of the early-music movement.

His music became a distinct brew of Renaissance pastiche, Romantic melody and Parisian harmonic bite, expressed subtly and in bright timbres, and all touched on by this sincere but erratic concert. Local forces led by Raymond Calcraft, "Exeter Ambassador" and Rodrigo specialist, recruited the Royal Philharmonic Orchestra and a guest-of-honour list that placed the mayor of Exeter above the Spanish ambassador. Twenty-one paintings by Nicholas Eastwood hung at the back of the platform, bringing colour to the stern decor and turning the event into a cross-art celebration.

The music did more justice to Rodrigo's sound-world and serenity of spirit than his flair and quick mind, though the first half dipped into the latter with two appealing items, including the UK premiere of excerpts from his light opera El hijo fingido. This expertly shaped score laid the composer's cards on the table with less harmonic spice than usual, and more glamour, from lush choral sequences to lyrical solos for mezzo-soprano. Rodrigo's use of trumpet and piccolo as lead wind instruments gave a brilliant edge.

What do you do about that guitar concerto in a centenary concert? Leaving it out looks perverse. Put it in, and it had better be done well. Calcraft brought in Angel Romero, one of Spain's finest, and the result was solo fire and virtuosity, matched by quietly pointed orchestral precision.

The rest of the event was variable, led by a dull cantata to commemorate the 1,700th anniversary of the University of Salamanca (despite Gerard Quinn doing his best with the bass solos), and ending with a stark setting of words by St Francis of Assisi. Rodrigo's last big work, the Cantico de San Francisco de Asis, begins with spare sounds and builds up for too long or, as on this occasion, too slowly. The Exeter Philharmonic Choir, reinforced with a few Londoners, achieved a fine internal balance and rather less purity of line.

The discovery of the day was a group of three songs originally dedicated to Victoria de los Angeles. The Triptic de Mossen Cinto sets words by Jacint Verdaguer, focused on the same pantheistic saint, and is absorbing through a piquant scherzo to a radiant finale. The few chord changes and glowing textures created an affecting and personal statement – the concert's best argument that here is a major 20th-century composer who is still largely undiscovered.