Hi barkar
No, the new lender is not obliged to offer you a tracker due to AIB's breach of contract.
However, after you get your letter, you should write to them as follows:
If you had not broken the contract with me, I would have availed of a trade up mortgage with you.
The interest rate would be [2.5%] on the trade up (It's whatever margin they give you +1% )
I have since paid 3.5% to BoI
So you owe me the difference between what I have paid BoI and what I would have paid you.
Also, I want to move back to AIb on a tracker of 2.5%.
Alternatively, I am prepared to consider a cash sum in full and final settlement and stay with my new lender.
Brendan