Which parts are you planning to upgrade?
Most laptops RAM and storage could be upgrade, including MSI, Alienware, etc. Other components (CPU, GPU, etc) might not upgradeable on any new or resent laptop model.
There are boutique models (above £1800) that may have upgradeable CPU and GPU.
There are no real upgradable laptops, and for sure not for your 200 budget. 200 is not even good for a basic use system past toy level. You may be able to get a used system for that much, I like the Lenovo T420 and T430 models in that range.