I seem to recall that you are the guy who resigned his job about 2 weeks before your employer declared redundancies. You were hoping that you are due some of it, and we advised you that you weren't. So you are now thinking that you might be able to claim constructive dismissal on grounds of bullying?
Extreme bullying may constitute grounds for constructive dismissal. It depends on what you can show you did to seek to raise the issue - taking a complaint through the grievance procedure, for example, and being fobbed off.
Frankly I think you've got no chance unless you raised it in your resignation letter. If a period of time has now passed since you resigned and you are now going back after the company has made an announcement regarding redundancy consultations, it just doesn't stack up.
Unless you can us tell it isn't like that.