Ulster bank say on their website “The monthly mortgage repayment installments will commence once the first stage has been drawn down and will be based, at any one time, on the balance outstanding spread over the original term”.
So if this applies to Haven you once the first stage payment has been made you repay €68K over the 30 year term so €270 ish a month. But maybe ask Haven?
30 years, 2.25%
Stage 1: 68,250. €270
Stage 2: 68,250. €541
Stage 3: 68,250. €814
Stage 4: 68,250. €1086
Stage 5: 20,000. €1165
Stage 6: 20,000. €1245
Snag List completion: 5,000. €1265
Apparently you are borrowing €318K not €300K