1.8T Exhaust maniford, leak ?

[P700DEE]

My 1.8T A6 120K miles started making a noise on start up back in February. It disappeared quickly and was intermittant. When serviced in May the garage noted a noise and detailed possible exhaust manifold leak. Now we are almost in August and the car sounds like a diesel on start up and I managed to spot a small amount of water vapour emitted from near the rear of the engine near the exhaust manifold. Anyone else had a similiar problem ? Was is gasket or cracked manifold ? Is it likely to be expensive to fix ?

Thanks