The remaining defence of relevance would be under section 122(f) and (fa) of the Trade Marks Act. It provides a defence to infringement where the defendant would have achieved trademark registration had it applied for it (in the face of the registered trademark being relied upon). That is, in the hypothetical scenario that the alleged infringer had applied for its own trademark registration at the time of the alleged infringement, would the alleged infringer been successful in getting its trademark registered?
Under this defence, the alleged infringer will often rely on honest concurrent use. In brief, the law states that if a trader has adopted a mark honestly, and used it for a sufficient amount of time concurrently with the prior trademark, then it should be able to co-exist with the prior mark in spite of their similarities.