Re: ICAO codes for Origin and Destination when passing details
Keygrip,
London Information has no radar and never will... it is merely, as the title suggests - an information service..... it carries out it's task under the provision of a Flight Information System.
(I say 'merely' in the loosest term as the chaps and chappesses who provide the service do so to a very high standard - they have charts of the area they are providing info for and can pass on potential hazards and warn of other aerial activity, but the provision of radar would need them to become licensed ATCOs)
As you rightly said - if people say destination/departure points in the clear, it gives others who are flying a bit more of a chance if they do not know ICAO codes.