Leak.... but what is it?

[babemagnet]

Bike has been sitting in shed since last july. has not got wet. Oil has just been changed and is a nice red colour still. After what has been said above I am also perplexed as to why it only seems to drain out when on side stand and not when in motion. I am now worried as am due to tour Spain at end of june and am now questioning whether it will do about 5000 miles. Should I fix before I go or will it last the holiday?