The hard part is that Caterhams fall under clones and not production cars. The whiskers weren't on Lotus 7s. The MAC has to be pushed for the A/B/D/EM rulesets to changed to a "if it doesn't say you can't, then you can", as opposed to the "if it doesn't say you can, then you can't" that is in effect for Stock, Street Touring, Street Prepared, Prepared, and Street Modified.
Joshesh - update/backdate doesn't affect 7 Clone aero because there is already a huge clarification 5 years ago. The resultant rules are either in the back of the Mod ruleset or in the Clarification appendix.