Remortgaging - who does the valuation?

We are due to remortgage next year. We have a 15% deposit (bought last year).
We got a good purchase price and have done a lot of cosmetic updating to the house. Estate agents locally value it at 10- 15% more than we bought it for. However market increase according to various websites is 1.8% increase.

If the mortgage company send a valuer how can they accurately value it without knowing the condition we bought it in and no local knowledge?

Thanks