  We discuss the notion of generalised U-duality as a solution generating
technique in supergravity. We demonstrate a method to take solutions of type
IIA supergravity on a 3-sphere, with NSNS flux, to new solutions of
11-dimensional supergravity, using exceptional geometry techniques. These new
solutions are characterised by an underlying 3-algebra structure, and
generalise features of solutions obtained by non-abelian T-duality, which
involve an underlying ordinary Lie algebra. We focus on an example where we
start with the pp-F1-NS5 solution in type IIA supergravity. We discuss the
properties of our resulting new solution, including the possibility of viewing
it globally as a U-fold, and its M2 and M5 brane charges. In the extremal case,
the new solution admits an AdS${}_3$ limit, which falls into a recently
constructed class of M-theory AdS$_{3}$ backgrounds -- this provides a global
completion of our solution with a well-defined holographic dual, similar to the
global completions of non-abelian T-dual solutions. Our full solution is a
6-vector deformation of this AdS${}_3$ limit. We also explicitly solve the
Killing spinor equation in the AdS${}_3$ limit, finding a $\frac{1}{2}$-BPS
solution.
