Check out their description of it:
https://personalbanking.bankofireland.com/borrow/mortgages/mover/starter-tracker-for-mover/
The Tracker for Movers interest rate is available on mortgage loans only for a house you or your family live in. You must have an existing Mortgage with the Bank of Ireland Group, with a satisfactory repayment record of at least two years.
If you keep the home you now live in and intend to let it out, you cannot keep the tracker rate from the tracker mortgage loan you now have: we will move you to our normal investment property mortgage rates instead.
So, in theory, they would refuse you and could say that you should have lost your tracker back in 2011.
In practice, none of the banks, enforce the investment mortgage rate on homes which are rented out.
The safest thing to do would be to move back to the apartment and apply from there. You would not have to stay there long.
But if you just apply for the new product without raising the issue that it is no longer your home, I doubt that they will query it. If they look at your bank statements though, they will see rent coming in and rent going out.
Brendan