Well done on the basics, good paint coverage, nice and smooth. Some thoughts in addition to the ones above:
Paint your headlight lenses silver
Drill out the main gun a bit, even if you just do a little with a sharp #11 X-Acto.
A dab of gloss black in the cupolla vision ports will make them look glazed.
Use a darker metal for the machine gun barrels so they don;t look so shiny.
Nitpicky here, this is Tamiya's kit, right? So the fault lies with them rather than you, but I don't believe the Brits used the sponson guns. Tamiya has never updated the molding or instruction sheet to allow for the easy removal of these.
Please take these suggestions as being constructive, since you've done a nice job overall.