In the first picture, unless you were using spot metering, the meter was telling you what to set the camera to in order to get a midtone sky. The lights (and the Eye) constitute only a relatively small portion of the image; to achieve an overall average exposure, the camera is telling you to significantly overexpose. The picture is probably still somewhat overexposed as shot unless it was a particularly overcast and smoggy night. If the Eye is bluer than you think it should be, you can put that down to the difference between the way your eye sees different lighting and the way the camera sees it. Note that in the building to the left, the light is too yellow, and the colour balance of the light in the smaller building at centre bottom is just about perfect. Different lights were used for each, and your eye doesn't see the difference in colour temperature nearly as acutely as the camera does (film or digital doesn't matter; neither does the lens). Since you won't have the budget to control all of the lighting, and you don't have a single main source of light to even everything out (like the sun), you'll probably find that the riotous circus of different lighting types used in the city is going to be a constant problem Remember that you can always fix that in post by developing the RAW image several different ways, with setting that best suit different parts of the image, then blend those various versions (sort of a colour-based version of HDR).
In the second picture, the exposure was better, at least for the Palace (the famous logo of the world's greatest brown sauce), but there is significant flare. It looks like you were using a pretty small aperture there (the "star" patterns around the brighter lights and the shape and size of the flare blooms are a giveaway). That is what's leading to the details in the clock, etc., being washed out. Diffraction around the lens's iris blades is causing the bright lights to spread out. In the reduced-size JPEG it's hard to tell for sure, but it looks to me like the focus is actually much closer to the camera than the clock* (somewhere closer than the bike lane marking, going by the apparent detail on the pavements and in the street proper just left of the centre of the picture).
So perhaps the pictures aren't what you were hoping for, but it's not the lens at fault. It's more likely that you have little experience shooting outdoors at night. The rules are not quite the same as they are during daytime. That is, circumstances are different enough that you really need to understand what your camera is metering, and how to "place" tones in the picture. The only way to do that is to take a lot of pictures, get a lot wrong along the way, and get increasingly more right with experience. It helps to keep a record not only of your camera settings, but of your assumptions and reasons for setting the camera that way, and the results you obtained -- even for images you don't keep.
* Big Ben is the bell upon which the hours are struck.