I need help with how much to offer

I decided I wanted to buy last week (before that I had been slowly researching in prder to buy next year, but have decided to move it to this year when my tenancy end where I rent).

The area I want to move is small, in zone 6 of London. I have found 2 two bedrooms I really like and will be visiting them this weekend. There are a few more options if I don't like those (2 flats I like less). Appart from that, I don't think anynother will come on the market,, it is mostly houses in the area.

Apartment A : share of freehold. Put on the market in July 2025, at £350k, reduced one month later to £325k

Apartment B : Leasehold. Put on the Market at £400k in July 2025 then reduced every month or so. August (£355k), September (£320k), November (£300k), February (£278k).

I will see which one I like the most but my gut feelimg is that I should try to get the freehold one? Would it be crazy to offer 8-10% less? Can you put sellers off by offering to low (in their opinion) and ruin your chance or is it part of the "game"? Or is it a done thing to make an offer (let's say 5% less then reduce it if the mortgage valuation is lower?

Also can you put offers on 2 flats at ghe same time?

How would you experienced people approach this (I wish I gave myself more than a week to figure all of this out)?