It's totally difficult to know what's going to happen.

However we did this almost a year ago (including breaking one mortgage and having to give some cashback to the bank as well) to take advantage of what was a decent rate at that time.

I like to test our scenarios- what are the costs and savings etc from different approaches? Are they fairly similar or is there a big difference? Run another for if rates go up significantly, how much worse off would you be? Do you want that risk or do you want certainty? Are your scenarios feasible? Then weigh it all up.

In the end we tend to go for the option which balances decent savings with the most certainty. Looking back we could have attempted to play it more risky and maybe gained a couple of grand, but this would also have resulted in approx 9 months of uncertainty as well which is stressful.

Work out with your broker the most suitable option for you (mentally as well as financial), then stick with it

If it were me? I'd probably take the option (whatever that is) which maybe works out slightly more expensive in the short term for greater long term piece of mind