getting the sketch out of an assembley?

Hi all, I know this should be an easy to do bit but its driving me mad! Ive made a sketch in an assembley before - and then opened it as a new part, to carry on modelling it. but the surface features just dont seem to be there. ive made the skeleton sketch so its all to the right places, now i want to take it out and carry on modelling it..............................

any tips would be great

thank you

andy

SolidworksAssemblies