Great to see a real example.
I'm open to correction on this, but I understand that KBC go through a complete underwriting process to issue an aporoval in principle.
Some lenders delay part of the underwriting until you have a specific property, so they can put in a clause.
In any case, the CBI rules are based on actual gross income, so would need to be back on full salary before drawing down if you exceed the 3.5 LTI rule without it (or apply for an exemption).