Hi G
That is a very interesting question.
You were given a higher mortgage than you would have otherwise been given, because you had a guarantor.
The guarantor is not engaging but you are.
KBC have no reason to offer you a split mortgage. If you can't make your full repayments, they can go after the guarantor.
Have you tried to get the guarantor to engage?
Can you show KBC evidence of your attempts?
If the guarantor has no money, KBC is more likely to give you deal. But if the guarantor is good, they won't.
brendan