If you really want to take ‘polishing’ to another level - relatively cheaply, you need something like the Silverline 1200W sander/buffer/polisher, invest in some 3M hook and loop pads and a 3M sanding disc pad. I’m guessing you are £100 in now. Then you need cutting polish and then a final polish. Meguires stuff is good but I’ve only used it for the last stages of finishing. If you want the car to look like it’s just been repainted (which might be £2000), you may have to spend £200 on gear and products and probably a day or two on elbow grease.