Owning your own home

mortgage split into two parts, where each part is with a different mortgage lender

I am not a broker but I would be extremely surprised if you can do this, unless one mortgage is first charge and the other is second charge. If you stop paying how do the banks co-ordinate on special servicing / reposession with pari passu loans?

The best deal they are offering on that is 2.14% (2yr or 5yr fixed). Seems like maybe we could get a better deal somewhere else? But not sure if it's worth the hassle of switching and then having a mortgage with two different lenders.

There are often other sweeteners to stay with an existing lender. Lower (or even no) fees for the new product. No valuation fees from the new lender. Moving on to a lower rate earlier than the usual time-limit (for avoiding early repayment charges), etc. Also the ability to do it all over the phone in a matter of minutes rather than days with paper flying back and forth.

Last time I remortgaged (with Santander) it was ~20 minutes on the phone, got moved onto a lower rate (1.94% down from 2.19%, 5 year fixed interest only) three months early, no valuation fees, I did have to pay a new product fee but I think it was discounted and was just chucked onto the outstanding mortgage balance.

Boringly just looking at our mortgage, we have 19 months before the early repayment charges go and we move onto a variable rate, but we're limited to paying back 10% of the outstanding capital per calendar year (it's an interest only mortgage) and since we have <7 years to go we obviously can't get to £0 outstanding if we can only pay off 10% a year. Plus we also blow through the yearly repayment allowance faster and faster now, in 2022 we'll hit the limit with part of September's overpayment, so the rest of it, plus Oct/Nov/Dec will go into a savings pot until Jan 1st where it gets dumped into next year's repayment allowance. This then means that in 2023 we hit the 10% repayment allowance in April, and so the money from then until the renegotiation (Nov 2023 if it's not early, but probably more likely 3 months earlier so August 2023). From there I've no idea what to do for the last 5 years. I like the security of a fixed rate, but need the ability to pay down the capital but like the flexibility of an interest only mortgage. A fixed rate interest only offset mortgage would be perfect, but I don't think they really exist. Guess I'll speak to my IFA next summer and get their advice.