I feel your pain. That kit lens is honestly frustrating for street work since the corners are just mush. Honestly, get the Fujifilm XF 23mm F2 R WR. It is way sharper and the focal length is just perfect for London streets. I had issues with focus speed on older glass, but this one is snappy. You wont regret the upgrade, really.

I messed around with both for months before settling. Here is how they stack up for street work:

• Fujifilm XF 23mm F2 R WR is wider, so it feels more immersive but harder to frame.
• Fujifilm XF 35mm F2 R WR is tighter, really crisp, and feels closer to how my eyes actually see things. Honestly, the 35mm feels more natural for quick shots. The 23mm was decent but I always felt like I was cropping too much later.

Like someone mentioned, the kit lens struggles with edge sharpness and honestly, I was let down too. I spent a good chunk of my budget expecting something stellar, but the results were just okay. Unfortunately, I had issues with the autofocus hunting in low light when I tried the older glass, so I ended up being way more cautious with my next purchase. My experience? I went through a phase of buying and selling because I wanted that perfect sharp look without dropping a fortune. I eventually picked up the Fujifilm XF 35mm F2 R WR because I needed something weather-sealed for the constant rain here, but even then, it wasn't as good as expected for extreme close-ups. It is reliable for sure, but maybe not the magic bullet you are hunting for. Quick tips if you want to save that 500 quid:

• Check the secondary market for gear that includes the original box, it holds value way better.
• Look for a reputable shop in London so you can return it if the copy you get is soft, because quality control on these smaller primes can be hit or miss. It is definitely frustrating when you see those crisp shots online and yours look like mush. Just dont rush into a buy, really take your time checking the used market stats.

Ok adding this to my list of things to try. Thanks for the tip!