Wildy:
Thanks for the reply. I’ve taken pics of the box.
The product on board is UN2000. And shown on DGN as such. Table tennis balls so weight approx 8ton.
Hi Wildy,
Thanks for the pics and extra info. 
Given that you picked up a container containing UN 2000 from a railhead, the required placards were 4 X 4.1, to be shown one on each side, plus one on the front and rear.
That would be all that’s required for a road/rail journey, as they are regulated by ADR/RID respectively.
If any part of the journey involved carriage by sea:
Then the requirements of the IMDG Code must be complied with as follows:
For amounts of dangerous goods up to (and including) 4,000kgs, the placarding requirement is the same as road/rail above.
IMDG requires that once the amount of dangerous goods of one UN number exceeds 4,000kgs, then the UN number must ADDITIONALLY be displayed.
When that requirement is triggered, IMDG says that there is a choice for how it can be achieved:
Option #1
A road/rail placard PLUS the four digits of the UN number (not less than 65mm height) on a separate orange panel not less than 300mm X 120mm like this:
OR
Option #2
The four digits of the UN number actually on the placard, but again not less than 65mm in height:
Either option is just as good as the other, IMDG doesn’t state a preference.