Would be interesting to see who warned you that you were being set up to get the sack. I think it's just employee speculation and nothing more as it is unlikely management would speak that way.
If the worst happens lodge a claim with the work tribunal straight away, you can always cancel later. If you do take it to tribunal you have to be really honest with yourself and expect both sides to come out slightly compromised, with the loser more compromised than the victor - that's how they operate. 14 years does hold significant weight at a tribunal if your record is clean.
In my sacking it came out in the tribunal wash that the HR manager got onto the phone to a lawyer straight away after a homo executive whom I've never seen or met decided he wanted to get rid of me. Of course the lawyer would say sack me as he would make a lot of money out of it - thereafter the rest was just a bogus charade. I received serious legal threats prior to the tribunal which I ignored. During the tribunal the lawyer was clutching at straws who if not attacking my personality would be looking at technicalities in the legislation - he even requested leave (delay) from the hearing. But representing myself I got 'em good and they coughed up loads of dollars - I made the 2% category.
Besides the win over 3 totally useless pieces of **** (lawyer, HR, executive), the experience was quite harrowing as I'm an engineer not a lawyer. I was always willing to drop the case had I found employment but my reputation had obviously been tarnished.