hello,
it aint the most glamorous solution but heres what we did,
found an old hover pipe ran it from the top of the snorkel sealed in with heat proof foam that was left over from fitting an airconditioning vent at my dads office, and ran the hover pipe all the way to the air filter throught the existing pipe, that way if your landy is same as mine and has wholes in this pipe you kill two birds with one stone :lol:, its cheap and as far as i can tell it works, i have done the test where you put a thick bin liner over the snorkel and the engine didnt stall but on further ivestigation the air was coming in from another location,
hope this is of help to you
cheers kieran