As a follow up. I did get a reply to my email informing me the plate holder clip thingy was being dispatched, but there was a late delivery in the US, who in turn hadnt informed Proviation. I followed up with a reply and asked why their website said the item was in stock, and is still in stock, but they had to wait for something to be sent from the US. They didnt reply
It seems to me that Proviation is just a middle man. You order from them, they take your money pronto, and then they order the goods from (maybe) multiple suppliers. This differs from Transair and FlightStore who presumably have a large warehouse with their own stock, and an up to date and reliable stock inventory system. I wont bother ordering anything off Proviation that I want ASAP. Transair will generally get you your stuff to your door within 24 hours.