Hello Hamish,
The tops on Topsonline are reproductions of tops for original MG-TDs. I beleive they will not work on your friend’s TD replica.
You might try MG Magic in Florida, phone 954-680-2010.
She might also try to have a top sewn locally. Any place that makes boat tops could probably handle the job. Some auto convertible top installers or interior restorers might also be able to sew a top for you.
For that it’s worth, as you learned on topsonline there’s no such thing as a 56 TD. MG made the TD from 1950 to 1953.
Good luck.
Paul Mossberg
Former Owner of a 1981 Classic Roadsters Ltd. Duchess (VW)
2005 Intermeccanica Roadster
If you own a TDr and are not in the Registry, please go to https://tdreplica.com/forums/topic/mg-td-replica-registry/ and register (you need to copy and paste the link)