I am no expert, but what you are describing is all too familiar.
Noting what you say about others in the company have been successful at their tribunals is it worth contacting them for contacts/tips etc? I am a firm believer in not 're-inventing the wheel' it is not necessary. Whatever legal help they got could be invaluable for you, being placed in a similar position.
I presume, as you have not mentioned it, there is no 'union' or other body you suscribe to that you could use to help?
Anyway good luck and I wish you well in what is an awful situation when you have given loyal service for so long.