Hello George
My experience with carpet is that it’s always better to use the old for a pattern. You can then take it someone or cut out some yourself. Be aware that most auto carpets are formed to fit over the tranny hump, foot well and sides so that a flat piece of carpet cut to the pattern may still not fit well. You can form the carpet to fit these areas your self with a little work and time. I’ve had good luck with other vehicles by simply stretching or forming the carpet over some scrap wood, lightly spraying the back side with water, then holding the formed area while drying with a hair dryer. Check for fit, redo as needed. Oh, be sure to leave lots of extra room at the edges so you can trim exactly to size after the areas are formed. This is what the auto shops do and you can save mucho $$$ doing it yourself. After fitting, place padding and glue or screw the carpet in.
As far as ordering ready made like you can for many cars, the TD replicas will have variable size tranny humps, foot wells, etc.,depending on the make, so it very unlikely you can find it anywhere other than maybe MG Magic in Florida. Give them a call, you might get lucky.
Good Luck and have fun with your new toy!
Ringo