I have only bought 3 houses in my lifetime. 2 were at asking price because the market was going up daily so to secure it we needed to offer asking price.
The house we are in now was on at £250k and we offered £235K because we had sold to cash investment buyers so no chain below us. Vendor came back with a no but we will accept £240K and we agreed.
But in reference to looking at what the houses have sold for previously it doesn't reflect the situation at the time unless you were keeping a very close eye on the market and the factors that influence it.
I am in the North and the reason my house was £250k rather than way over £300k was because the local primary school was dire, was a mixture of old 60's building and porta-cabins. It was listed as requires improvement by Ofsted.
Since then the school has been demolished and completely rebuilt, is stunning and is now outstanding by Ofsted so houses within catchment have increased considerably. We are also in catchment for the outstanding secondary which is always oversubscribed. Those two aspects mean you can buy and not have to move. We actually moved here for the outstanding secondary but kept our children in their outstanding primary 3 miles away.
The deal is house prices are bizarre that they seem to fall into logical numbers rather than £232,750. The offering 10% could be a lot depending on how much the property is listed for. And yes, you can piss off a vendor who doesn't want to deal with you for further offers. If you put in a piss poor offer and then negotiate your way up, that vendor knows the minute that survey comes in you are going to be dropping that offer way back down again with every tiny detail.
It all comes down to how much you want the house. I am sitting in my forever house, and we went into temporary accommodation to get it.