When examined by BBC Radio 4's Document programme, the format, language and tone of the documents all rang true, but establishing whether they were genuine was not simple: MI6 never discusses its operations or declassifies files and all the people named are dead.
The format of the programme was changed to 'Sounds Like Saturday Night' and this gave Dave a bigger reach with his musical knowledge to include the 50's, 60's, 70's, 80's and beyond.