To ask for a discount so early on (house purchase)

[Acheess]

My offer was accepted 2 weeks, and nothing much has happened as i went on holiday.

This Property was on the market for £435k and my offer of £405k was accepted.

Today, a neighbouring property was posted on Rightmove, and while the internal layout is the same this new property is in much better condition: it looks cleaner and is fully redecorated; the property I'm buying looks tardy in comparison and will need some minor work.

This property has been listed at £425k, which makes me think it will sell close to what i offered (£405k).

I feel I'm overpaying and am tempted to ask for a discount, but, I think, it will be viewed as cheeky as the offer was made 2 weeks ago.

Am I being unreasonable? I don't want to lose out on both.

For all the sellers who have been dicked about, did you know that you can insure yourself against purchasers like this?
So many people think they will take you to exchange then drop the price on you, so that you lose money and the property you were buying - it's heart breaking, stressful and costly.
There are insurance policies that cover you against chancers - they are not ideal, because there is some leeway for the price drop before the policy kicks in, but it does cover some of your costs. Best not to let the purchaser know you are covered, so that they cannot angle the value of the price drop.

Lots of "ifs" view it offer on it go from there , it might go for more than asking, it might appeal to more ppl so more competition ? It might have issues ?
Lots to think about but also comparison is the thief of joy,

Tardy means delayed, ergo it’s impossible for a house to be tardy. If I were your vendor and you asked for another reduction on nebulous grounds I’d tell you the property is no longer available to you on the basis that you’d be a pain in the arse throughout the entire process.

I wouldn't be overly concerned about both houses going on the market fairly close together. This often happens, when neighbours see a house has gone on the market and sold fairly quickly, and at what in their opinion is a good price, and if they've been thinking of moving too, for whatever reason, it's often the spur they need to put their own on the market. I've moved quite a few times, and it really does happen quite often. It could of course be that there is a problem in the road/area, but maybe knock on at a couple of houses in the street, and have a chat with your prospective neighbours, tell them you're hoping to move there, and ask if there are any problems locally, like kids making a nuisance of themselves, burglaries, etc. It's often worth researching police reports in the area in general to see if crime is bad too.

Are you a first time / cash buyer OP?

If you are now not happy with the offer that you have made then I would let the vendor know ASAP. They may potentially look at their pricing or they may tell you to jog on and put the property back on the market. Either way at least you will have been upfront before the vendor (and any potential chain) incurs more cost and wastes more time.