I tend to agree with ClubMan's response, but there is another option you could consider: you could have a split rate, i.e. fix the bulk of the mortgage (maybe 60 to 75 percent of it) and leave the rest on a tracker rate. That leaves you with a fairly good level of predictability on your payments, but increases your flexibility - if your incomes go up or you have a small windfall, you can pay extra off the tracker portion of the capital. I don't know if those specific lenders do split rates like that, but there's no harm in asking...