Hearing Beethoven’s piano works played on instruments he would have known was an exciting novelty 40 years ago thanks to the early experiments by Paul Badura-Skoda and Jörg Demus (on not-terribly-well restored Conrad Grafs and Broadwoods), which despite their jangling tone and rattly action gave us the startling revelation of the true “una corda” pedal and the sensation of the wild composer-pianist stretching the possibilities of the instrument to near breaking point.  Thanks to the advances in sensitive restoration, and some marvellous craftsmen building impeccable copies, we now have more sense of the peculiar characteristic beauties that were lost in the search for improvements in volume and evenly graduated tone while the more polished results carry their own musical validity.  Ronald Brautigam has proven this with his marvellous survey of the complete works played on superb sounding copies by Paul McNulty. With the masterworks now all dealt with we are coming to the fag end of the series, but there are still plenty of delights revealed in fresh colours and the particular tonal qualities and domestic nature of the fortepiano elevates the most slight of Beethoven’s scribblings. This volume might seem a mere completist appendix but makes a delightful 68-minute…