Finally recieved word back. So all thanks to the RAFmuseum for answering:
Dear Mr. Vangheluwe,
Thank you for your enquiry. Items carried by RAF aircrew flying over
enemy territory included their two identity disks, survival equipment
(e.g. parachute, life jacket and whistle) and escape aids (e.g. maps,
compass, emergency rations, foreign currency and passport photographs
for use in forged documents). For further details and photographs of
some of these items I would recommend the book Luftwaffe vs RAF: Flying
equipment of the air war, 1939-1945 by Mick J. Prodger (ISBN
0764302493). The dinghies carried in larger aircraft contained further
survival items, e.g. flares, radios, food and water). Sometimes they
also carried blood chits (messages in local languages urging civilians
not to mistreat downed aircrew and return them to the British
authorities). These are described in Last hope: The blood chit story by
R.E. Baldwin T.Wm. McGarry (ISBN 0764302221).
Aircrew were encouraged not to take any documents with them as they
might have revealed information to the enemy if captured:
"Don't carry or allow anyone else to carry any papers, official or
private, on a flight. An envelope may give away information. Everything
gives something away, even an old Tram Ticket or a bill. Don't forget
to turn your pockets out before going up as a matter of routine even if
you don't intend to go over enemy lines." (Sub-Air Publication 1548;
Instructions and guide to all officers and airmen of the Royal Air Force
regarding precautions to be taken in the event of falling into the hands
of an enemy; 1940)
greetings Arneken.