Someone is using my company name is this allowed?

[Eric Mc]

If they were using the name purely as a "trade name" and were not using the "limited" bit in the title, then, they haven't actually contravened any regulations or laws. However, if you are particularly agrieved by this behaviour and feel that they may be trying to mislead customers or suppliers or "pass themselves off" as your company, then you could apply for a court injunction to make them stop.

This has been done succesfully on many occasions.