The two routes
A product transfer is a new rate with your existing lender. Same loan, same charge on the property, no conveyancing and usually no new valuation. With no additional borrowing it needs no affordability assessment at all. It is the smaller job and, in the second quarter of 2026, 81% of all refinancing went this way.
A remortgage is a new loan from a new lender that pays off the old one. Income evidence, an affordability assessment including the stress test, a valuation the new lender instructs, and legal work to discharge the old charge and register the new one. It is more work, it can fail, and it costs money to arrange. It is also the only route that gives you the whole market, which is where the best-buy rates live.
Price every fee on both sides
The costs to check: the early repayment charge on the old deal, which is never covered; an exit or deeds release fee; the new lender's arrangement or product fee; the valuation fee, often free on a remortgage; legal fees, often covered by a free-legals package; and a broker fee, which many brokers do not charge the borrower.
The arrangement fee is the one that catches people. In September 2026 the best-buy two-year fix at 4.66% carried a £1,124 fee, and so did the best-buy five-year at 4.70%. A headline rate with a four-figure fee attached is a different product from the same rate without one.
Ask your own lender first, with the quote in your hand
A phone call that says "I have been offered this rate elsewhere, can you match it?" costs nothing, and if it works there are no switching costs at all. Put the rate they offer into the product transfer box and set the fees to zero.
How long an offer lasts
A mortgage offer is valid for a limited period, set by each lender, commonly somewhere between three and six months. There is no published UK-wide figure, so do not rely on a number you read anywhere, including here. Ask the lender in writing and put the expiry date in your calendar.
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