Cross secured
Like a lot of people like you are assuming that your properties are not cross secured. Wrong. In Ireland you will be liable if you default on your investments and they will go after your PPR or vice versa. So paying off one and letting the others slide is Never an option.
I dont think this is a full picture regarding cross security.
If a loan is secured on a property, the lender can seek to repossess that property if the loan is not being repaid.
However if the loan on your PPR is up to date the EBS cannot seek to exercise their security over the PPR.
If other loans are behind on buy to lets then EBS would have to go through a process on those, i.e. sell the buy to lets and then pursue you for the shortfall before they could get into court on your PPR. And all the family home protection legislation would be in your favour. I dont think that family homes are often repossessed to pay debts which are not secured against them.
Bronte is right that you still owe the money and they can go after your PPR, but it is a much longer road than if there was cross security.
How important is this difference, well I suggest it is the reason that EBS wanted you to go interest only on the PPR instead of the buy to lets.
Regarding the rest of the tread a plan seems to be evolving to improve cashflow and pay off the debt over a longer period.
If you do adopt such a plan, it is up to you to implement it. Make your plan, tell the bank what you are doing and do it, dont think in terms of asking their permission.
I suggest that the first part of the plan is to pay capital and interest on your home. After all saving your home seems to be the main purpose of the plan. Then pay as much capital as you can afford on the buy to lets.