The definitive answer on Rear View Mirrors, from the Dept of Transport:
For cars & dual purpose vehicles up to 2040kg:
First used before 01.06.1978: 1 External Offside plus 1 External Nearside or 1 Internal Mirror Standard A
First used after 01.06.1978: 1 External Offside plus 1 External Nearside or 1 Internal Mirror Standard B
First used after 26.01.2010: 1 External Offside plus 1 External Nearside plus 1 Internal Mirror Standard D
So only the second regulation relates to Calibras. However, it is worth noting that the law changed in January of this year.
A - Internal mirrors must be surrounded by some material so that it is unlikely that severe cuts will be caused should the mirror be struck by any occupant of the vehicle.
B - Mirrors must comply with the requirements set out in item 2 of Annex I to Community Directive 71/127 or 79/795; or Annex II to Community Directive 86/562 or 88/321; or paragraphs 4 to 8 of ECE Regulation 46.01.
D - Mirrors must comply with the requirements set out in Annex II to Community Directive 2003/97 or 2005/27; or paragraphs 4, 5 and 6.1 of ECE Regulation 46.02.
