From what I can tell - after doing some digging around - that this may be an extremely small company. Various WHOIS searches reveal that this company goes by many names: Worldzone, D&B Graphix. The company appears to be currently located in a residential area, although another address (at Orbital House) only reveals one company - Kingston Smith.

The current address, 3 Mildmay Road, reveals another company at that location - Premium Network Solutions. Their number is 01708 737575 - you might like to try it and see if they will transfer you or can confirm whether BatteryTrader is located in their building.