I use a Cobra style rearview mirror because it has a greater adjustment range than an orginal style TD mirror. You can get it from Cobra Accessories http://www.cobraaccessories.com , their part number MR600. It sells for $17.00 and is on this page:
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)