How do valuations work at remortgage time?

[MuddyMay]

Does the bank assign a value, do they come out to see it, can you challenge it etc etc? Please tell me all! Thank you.

They come out to see it if they want.
mine was way undervalued but we couldn’t contest (we were in the middle of renovating)

I recently remortgaged with Barclays and they did an instant desktop valuation over the phone (increased by around 20% in two years) then advised I could remortgage at a lower LTV rate. It took minutes!

We are currently remortgaging with Nationwide. They sent a valuer out and we got the valuation within a couple of days. No issues with the valuation either.

Good to know, thank you!