Thanks for your replies guys which I will respond to in order. IanField....no Phillips screw unfortunately and spare wheel gives no useful info either,,,,normal steel wheel and all wheel studs showing... "wtf would happen if you had a blow out on the motorway??" well in normal circumstances you would have the wheel lock nut key in the car that removes the alloy plate so you could get access to wheel studs...my problem is I do not have the key or know the manufacturer to order a replacement key,,, gjnorthall...the "object" in the six o' clock position is the wheel lock nut to which I do not have the key for to remove Big Kev ...I am new to this type of vehicle so not really qualified to give an intelligent answer to your question about road noise because I can only compare the tyre noise to normal tyre's on normal saloon type vehicles but I would have thought the noise was not excessive Update ...I have just received a reply from an owner of a Rav4 with the same type of wheels from another source who advises me that the plate does not prise off and something like a Torx bit might remove his wheel lock nut whereas mine requires a "female" type of key... manufacturer not known. Previous owner of 4 years standing can not help either... which beggars belief .