OK, my book is stuffed full of references to dead actors, real restaurants, real places and it contained lots of Klingon with a smattering of Vulcan.
On the first big rewrite I took out the Klingon and inserted a language I invented (Xhovain) because Klingon and Vulcan are copyrighted.
But there were other issues.
So, what did Jambo learn today?
On using real people, names and places
You can use the names of dead actors (like Alan Ladd) but you should refrain from having them do anything bad or disrespectful. There will be the family of Alan still around to sue you, they may not be able to do so legally but have you got the money to defend a case in America? Me neither. In my book dead actors are used to make Retro-Movies – since this is actually starting to happen (is someone hacking my manuscript?) it may not be long before dead-actors names are copyrighted.
You can use real locations, like Starbucks, because the name is in common usage. Always use it capitalised as Starbucks and not starbucks. For years the Hoover Company had a team who trawled the media making sure Hoover was always capitalised. If you use a real location do not be derogatory in any way. if you have a lot of action in a specific real place (I have a whole scene set in Georgia Brown’s in Washington – the best southern style cooking north of the Mason-Dixon line) try and get their permission and assure them that your work will be like an advert for their place.
You can reference main landscape points, like The Empire State Building, but there is an ambiguity around whether you can murder a character in there. Since many movies show mayhem in public places it might be OK, but then again the movie producer might have cleared it with management first. Remember that Donald Trump, like all rich people, can be litigious (and rightly so – said Jambo covering his a*se).
I got this information from my friends at Critique Circle. That is a fantastic place for writers – the depth of knowledge about all things written is astonishing. I could have gone to a lawyer but all the ones I know have 3 hands – left hand, right hand and ‘on the other hand’.
So on with the final rewrite and I can keep some of my best scenes thanks to the advice received.

Informative, looks like I’ll come to your site instead of a lawyer when I write my first full-length. I’ll certainly take the time to read your stuff, cheers mate.