Martyn. Surely it is up to the manufacturers of "car bodied" reverse trikes to take this up with the EU (and for that matter the USA) regulation makers.
There are too many grey areas and a lack of uniformity in the current ruling if applied to vehicles like the M3W.
Personally whilst I don't like the moustache and the indicator light stems (solutions for both could have been designed better IMHO) I think the Australian regulators have set a pretty good precedent to follow.
You'd think so wouldn't you. But MMC did not seem unduly worried when the 3rd Directive was pointed out to them, shortly before implementation.
I do though think if your Transport Ministry is anything like ours, a concerted push from fellow Italian enthusiasts ought to get the derogation adopted. It's all there in the directive after all, so other than saying from date X and issuing a notice, not much actual work has to be done.
addedI don't think though you should be using the term, 'reverse trike'. While the type with a single front wheel are less stable, they do exist, and there could be (ok, a bit far fetched I know) a Reliant Regal in Italy.