ecamsurprise is definitely correct. You either go flexicrew for minimum 12 months in the UK or onto a permanent contract abroad. Recently a CTC white tail cadet type rating were offered basings in CDG, BCN or OPO - all on permanent contracts from the word go. However in this case you would forefit your 'security bond' which is given back in the form of tax relief on a UK contract after the flexicrew
It is not possible to be based abroad on CTC Flexicrew.