Re: Swanwick ATC frequencies (LACC)
Have spent years and years listening to ATC on the airband. For my enjoyment only. Never thought about passing on info to a third party.
I hold an radio amateurs license, know all the rules about listening and transmitting and in my book, if done carefully (and without telling Tom, Dick, Harry et al down the road what you do), shouldn't be a problem..
Funnily enough, there are many, many publications aimed at the airband listener/scanner enthusiast written by qualified ATC people readily available from High St newsagents/good bookshops.
It can't be that illegal if you are able to purchase a book with all the in's and out's about ATC - they all carry a forward message along the lines of "Watch what you do when listening - and be descrete"
Can't offer much more than.