I am suing a sole trader under his trading name. He has now formed a limited company using the same trading name. Can I still pursue him under his old company name?
Names are one thing, legal identities are another. It would appear that you are dealing with two legal persons, the sole trader and the company. The fact that they share a name seems likely to be immaterial. If that is right, then any ongoing claim against the individual shouldn't be directly affected by the newco.
Warning: I can't be 100% sure about this answer without knowing all the facts, so please treat it with caution.