You have no right to move your tracker.
PTSB has no barrier to allowing you to move it. If they want to do so, they would be able to do so.
As you have a RIP mortgage on your original home, ptsb may simply refuse to allow it to move. If they do, there is very little you can do about it.
I think you need to be upfront with them.
Is your current home on a tracker? If so, then you should be allowed to transfer it to a new property.
If it's not a tracker, sell it and move back to your original house. If ptsb allows you to port it to a new house, happy days.
If they don't, rent it.
Your current home may be cross secured on your original home.