well then no one is going to buy OP's house in this current market then are they lol. people who were looking for properties in the £500-650k two years ago (like OP themselves) could afford them on the lower 1% interest, but today OP will be finding that in this price range, these same buyers are either purchasing cheaper properties or flats, or sitting and waiting it out. everyone knows there will be a MAJOR price correction, even crash and OP is best advised to see what is happening in the market with buyers and their affordability. unemployment has also gone up in the UK/england and we are in a non-technical recession, heading for a technical recession. it's buyers who are laughing. it's a buyer's market.
OP also stated they got there house for around £485k or something similar in an earlier post in 2020 lol. it is delusional - at best - to believe it is £635k today. as someone already above said, the EA who quoted OP about the value of £535k (even less) sounds about right, and even then, it's overpriced given the current interest rate. another 2 EAs will say the same. the EA knows the buyer will negotiate less.
Based on my way of working out the value of the property, it aligns with the EAs thoughts that OP used. Your method sounds more like a guessing game to me. On the contrary, I use 'affordability' as the biggest factor because that's what the housing market is always based on: what buyer's can afford.
Or, OP could just list the property at £635k and wait many many months with lots of reductions appearing via PropertyLog that buyer's can see and will sit on. That will definitely not help it sell.
ultimately, in Sep 2023, prices have now dropped down to 2020 level and this is the reality sellers are having to face. i've been seeing it everywhere. it's just going to get worse for sellers.