How does remortgaging work?

[BadgersBiggestFan]

Can you find out from the lender what they’d value your house at before going ahead or do you just need to look at Zoopla?

Can anyone tell me what the process is please?

Most lenders will be able to do a desktop valuation to give you an idea of current LTV. Just ring them.

The desktop valuation as referred to above is a lender using something like this www.nationwide.co.uk/about/house-price-index/house-price-calculator
You plug in the date it was last valued, your geographical area and it'll give you a rough idea of what it's worth (unless you've done works/ renovation etc). Then look at rightmove sold prices for properties in your street / local area and as objectively as you Can, compare your own house to those sold.

Once you decide whether or not to remortgaged the lender will usually formally value your property via a surveyor.