Hello! I'm a new subscriber, but a long-time modler. I just wanted to compliment you on a nice build. I'd bidding on the same kit on ebay at present. My uncle had a 1958 TR3A when I was a kid... black with red upholstery and a white top, as well as the first set of Michelin Xstop tires I ever saw.
I was a graphic designer by prrofession, and one of the things I learned in Color Fundementals in college is that the smaller an object is, the darker a given color looks. It's just a trick the eye plays on us. Real BRG would simply look too dark on a 1:24 scale model. This is why auto touch-up paint makes a model look "funny". Colors need to be backed-off a shade in Value (lightness / darkness) to look correct. Also, here's a tip for all readers I learned building model airplanes: black (even "scale" black) is too black to realistically represent rubber. Try using Dark Umber acrylic from a craft store for rubber trim, tires, etc. Results in a much more scale appearence. You can always add a little black or charcoal (warm) gray. The Martha Stewart brand is splendid if your can find the color you want in the desired refelctivity. $2.00 for 2 fl. oz. vs $4.00+ for 0.5 fl. oz. of Testors. Any brand of "oudoor" or "patio" paint is not delicate once it has cured for twenty-four hours. 50% rubbing alcohol is an excellent reducer. Not knocking Testors or Tamiya... I have a paint case full of both.
You are correct about doping the plated parts with Alclad because the "chrome" is too intense. I have found that Alclad lacquer works best over a smooth, dark surface. The darker and smoother the substrate, the better. Even Alclad suggests using their shiney black primer for best results.
BTW, the trim between the fender ("wing") sections on English cars of that period is called "welting", and the padded finishing trim around the cockpit is referred to as "coaming". Uncle used to buys rolls of welting from J. C. Whitney and it came in various colors. Pre-war American cars used the stuff too.