I don't dispute that, I'm just keen to ensure that it doesn't take over the thread, to the detriment of other defence points that, pragmatically, might have a greater probability of success.
Many judges, especially at County Court level, are keen for an easy life. Ensuring at least one of the defence points allows them to find in the defendant's favour without "rocking the boat", is sensible.
Tl;Dr - by all means include it, but let's ensure it's as part of a fully fledged defence