Sorry I don't know but if someone has access to packaging info it should be easy to find out. The container 335 Mk 1 is a rolled paper cylinder and would therefore most likely be an inner container from a wooden or steel ammo box. The SV prefixed numbers relate to design or drawing numbers and if the drawing SV 246 A could be located it might well say on that what the 335 Mk 1 was designed to contain. Later, such information was given in Part 1 of the RAOC Statistics pamphlet. This lists ammo by nature and type, the packaging it was contained in, the Net Explosive Quantity (NEQ) per 1,000 rounds, weight etc. If the 335 Mk 1 was still in service from, say, 1975, then it may be detailed there. Yours reminds me of the 2 inch mortar inner container but I believe those were grouped in pairs that were connected together, three bombs in each cylinder, six bombs to a carrier and three carriers to a box, and I can see no sign of that on yours.