The most intriguing musical instruments in any London museum are the collection of keyed trombones (right) in the Horniman Museum. The excellent and child-friendly collection of world stuff, music stuff, and stuffed animal stuff, is just yon side of Dulwich in the south of the city.
Intriguing because, as the card (right) informs you, 'Specially shaped valve trombones were designed to be played at times when moving a slide was difficult, such as while marching, riding, cycling or playing in orchestra pits'.
Music for a cycling trombonist? Guaranteed cult status awaits any young composer.
If you're inspired to cycle there, the museum has decent onsite Sheffield stands.
The area also offers some sweeping, and surprisingly elevated, views of the city skyline. Not just from the museum gardens (right, which were delightfully snowed over and full of tobogganing kids over the weekend), but also from Ringmore Rise on the other side.
But if you're cycling up there in this weather, be prepared for tricky use of the slide, even without a trombone.