Gundog, the new Kynamco stuff should be readily available from Galazan and others. Vintage stuff is another matter. It seems to be much harder to find than vintage .416 Rigby ammo. I don't recall ever seeing any vintage Kynoch in .350. I've only encountered vintage .350 in the plain white Rigby boxes. I bought some Kynamco from Galazan some time back.

Have you picked up an original .350? If so, let's have some pics!