Broker, Direct or Existing (AIB) to fund extension

[David_Dublin]

Hi - current mortgage with AIB. Probably around 10% LTV (€100k mortgage (tracker), €1m valuation). We're planning a big job on the house, no tender prices yet but estimate it will be circa €400k max/all-in. Cash savings of circa €250k so plan to borrow around €150. A few questions:

• Is there merit in just keeping it simple - borrow the €150k from existing lender AIB, transfer savings (currently with KBC) into a new AIB savings account
• If I don't go with AIB, is this a complicated type arrangement that would be better to use a broker for?
• How does one approach drawing down (stage payments?) when so much is funded by savings? Does one spend all the mortgage money first, then the savings, or vice versa?
• Any advice on borrowing more/spending less of savings so we end up with some rainy day fund/savings? Should we maybe borrow more on variable and then convert to fixed when the job is done?
• Ultimately, the plan would be to borrow on a fixed rate for 10 years, and term as long as they will give us.

Info on us: late 40s, 2 kids secondary private schools, enough disposable income to borrow what we need up to a point.