Fiesta st150 possible air leak

[phoenixcoleman]

HI when starting my car the revs stay high and a hissing noise comes from the inlet area. Had the rac out he had his hand over the throttle body and it didn't cut out so he said there must be a leak from the inlet but before I take it to the garage I thought I would ask here. There's a vid at https://www.youtube.com/watch?v=OHYs0hP05lA thanks