Today's interpretation is brought to you courtesy of my brilliant sister Arlene! And here she is....
It might seem that at least the English portion of this Welsh sign does not need interpretation. However, a better understanding of this sign and all of it's implications will save you from a lot of pain and inconvenience.
Imagine that you need "heavy goods" delivered directly to your home; Say, perhaps, anvils. Alas, the Anvil Delivery Truck is not allowed in. You could try to hand carry the anvils in, but that often leads to smashed toes.
One idea might be to try to make a case that the anvils reside in the residential area, and as such are not violating the rules in any way. Good Luck with that.
The Welsh portion of this sign is more understanding of this type of difficulty.
If your Welsh has grown a bit rusty, I'll help you out.
"I am not in the office at the moment. Please send any work to be translated."
Hence, all you need do is pretend that you only speak Welsh, and that the anvils really need some translating, and could they please wait in the office for a while?