Nearing a half-century of existence, the Kensington Symphony Orchestra ends its current season with a tantalising coupling of very different symphonies: Sibelius No. 6, a polyphonic masterpiece that is cool and beautiful, and Tchaikovskys thrilling and passionate No. 5. The Kensington Symphonys status may be amateur, but it reaches a very high standard of playing, musicianship and commitment and its long-standing conductor Russell Keable has produced some memorable results over the years. If youve not been to a KSO concert before, this one on the 28th at St Johns, Smith Square (the KSOs regular venue), could be a vibrant introduction to fresh and distinctive music-making from a band that has a loyal following and is ambitiously minded as its wonderfully adventurous new season shows.