When is a Part 36 offer not a Part 36 offer?

The recent case of De Sena v Notaro is a useful reminder to litigators of the pitfalls that can befall not only experts themselves, but the litigators instructing them.

Interim injunctions are often granted in intellectual property cases. In an ongoing patent dispute Neurim v Generics, an interim injunction pending trial was refused and this has been upheld on appeal. How were the tests set out in American Cyanamid applied?