What's the likelihood of you moving house in the future? You could fix with Avant's One Mortgage for the remaining life of the mortgage. In order to lower your payments, extend the term. You could use the certainty to e.g. maximise your pension, if you have scope, knowing you could plan into the future. If rates come down, you could pay the break fee (Avant cap this at 2% of the remaining balance, I believe).
The more I think about, the more I think its madness to expose borrowers to interest rate risk - particularly, variable rate policies are a gift to the vultures. Longer term fixes are the way to go.