My client wants to incorporate their existing sole trade and so I am considering tax efficient ways of achieving this, including incorporation relief. The trade has various debts including bank loans and I would be grateful for clarification as to how these interact with the incorporation relief

As you mention, there are various ways to incorporate a trade, a gift, a sale for consideration or a sale for shares.

Ideally, there should be a formal deed of gift or contract for sale and so legal advice will be required. It may be possible to rely on a de-facto transfer, but this will be dependent on the actual facts involved.