From what I read this limited protection only applies to Lambretta dealers etc that predate the granting of the TM and only if they do not have the trademark "Lambretta" in their name.
A breakdown of the TM situation can be seen here
LambrettaTM
Mr. Kunman (owner of the Lambretta trademark) states his position as follows: “…In a nutshell, if any person/s were to make any product that infringed our trademarks, then we would take immediate legal action. Our lawyers are currently surfing the net, to compile a list of such offenders. We estimate that the legal costs will run into seven figures, all of which will be payable by the convicted offenders. We have a £20 million expansion plan, to increase our overseas presence. We therefore cannot be lenient with any trademark infringers.”
Another except from the above
What is clear... if anyone happens to call themselves ‘The Lambretta Garage’ or something of that type, without permission from Mr. Kunman’s companies, then it would be infringing his registered trade mark rights and they could be sued over it. The exception, at the moment, is that you can sell second-hand Lambretta scooters and Lambretta parts, as long as you aren’t called ‘The Lambretta Garage’ or ‘The West End Lambretta Workshop’ and, again, that you don’t display the Lambretta logo.
In my opinion, it's a difficult one to get around. This domain registration was made after he was granted his exclusive TM rights, and the domain name contains "Lambretta" which means it is probably not covered by the exception. As soon as this is spotted they'll more than likely issue a C&D, and would you honestly fight the case for a .org given his financial clout and the intentions stated above?
Up to you I guess, but I still say that the name is a liability, but maybe it's worth talking to David Williams about it?