You’re taking my words too literally when I said “tell the seller”. As I said, no one is right or wrong. When I’m involved in the buying or selling of anything I can’t be arsed with people trying to haggle me down, and likewise I always offer the asking price. I guess I’m viewing this purely through my eyes. I should have mentioned the caveat of offering the asking price if it’s fair. I did once offer below because I thought the seller had over priced. I offered a fair price with an explanation, with evidence, and said if they wanted to sell at this price they had a deal. I bought the place.The point I was making is you don’t make an offer straight to the seller (unless he’s selling privately) - you make enquiries whether the seller might accept a lower offer through their estate agent - that way you can find out before making a formal offer whether a lower one would be accepted for this or that reason ( and then make the offer formally through your solicitor obviously) .
Asking the agents if the seller might go lower for a cash sale, or other valid reason, doesn’t make you not look serious, it makes you look serious and sensible (and sellers will expect you to reduce your offer if there’s a £20,000 maintenance works planned or the property needs a new boiler)
I have been dead serious about all the properties I have bought over the years and only paid the full asking price on one of them for legitimate reasons.
But as you say, it’s your choice and a property is worth whatever someone is willing to pay for it.