Highly unlikely to have a leakage in the lines. However at the joints and connections it there could be. One method is to make or construct a pressure guage. Connect it in the bay and look for dropping pressure over night. If reduced check for leakages beyond that point all the way to the trunk. Once found seal it up again. Buy new lines; another method will be the regular bubble method-however that would take you a month. Goodluck.
240,000kms and 2001 pd; better get it professionaly inspected as well.