Indeed chaps, TCAS 2 is vertical gudance only. Best complied with because the information is up to date within milliseconds as opposed to atc instructions. However, the first thing we are told to do in the event fo a TA in VMC is to LOOK for the other aircraft. If spotted all future commands may be disregarded at the pilots discretion.
However, arguing against a TCAS 2 RA in the office or in court afterwards is going to need some real solid justification. Unless the TCAS 2 unit was confirmed to be playing up.
That said, who's to say MMENCLLBAMAN didn't experience one of aviations popular visual illusions.