  We study RG flow solutions in (1,0) six dimensional supergravity coupled to
an anti-symmetric tensor and Yang-Mills multiplets corresponding to a
semisimple group $G$. We turn on $G$ instanton gauge fields, with instanton
number $N$, in the conformally flat part of the 6D metric. The solution
interpolates between two (4,0) supersymmetric $AdS_3\times S^3$ backgrounds
with two different values of $AdS_3$ and $S^3$ radii and describes an RG flow
in the dual 2D SCFT. For the single instanton case and $G=SU(2)$, there exist a
consistent reduction ansatz to three dimensions, and the solution in this case
can be interpreted as an uplifted 3D solution. Correspondingly, we present the
solution in the framework of N=4 $(SU(2)\ltimes \mathbf{R}^3)^2$ three
dimensional gauged supergravity. The flows studied here are of v.e.v. type,
driven by a vacuum expectation value of a (not exactly) marginal operator of
dimension two in the UV. We give an interpretation of the supergravity solution
in terms of the D1/D5 system in type I string theory on K3, whose effective
field theory is expected to flow to a (4,0) SCFT in the infrared.
