Are you buying it together? Do you both intend on contributing to the repayments? Then get a joint mortgage unless one of you has a bad credit rating.
If you have a variable mortgage, you can pay in lump sums at any time. It is under the fixed term interest rates that there are penalties (or they recoup the interest they would have earned) if you pay it off early. That applies to all banks.
I hope this helps.
Steven
http://www.bluewaterfp.ie (www.bluewaterfp.ie)