Just an update on the problem. Took the nav to plazamaman during the week. What the discovered is the intake diameter is smaller then previous models by 5mm. So their silicon adapter was too big. Swapped it over no questions asked. He was very apologetic and told me if anyone on here is having issues to ring them up and they will send new silicon joiner out.
On a side note spent about a hr there speaking with him. He has a nice d40 with 130rwkw, and was telling me about plazmaman future planning for the nav. On the cards is a air intake pipe and box that connects to snorkel aswell should give one hell of a whistle. inter cooler and piping upgrades and a few other bits and pieces