in the build list is says 5mm x 16mm flange rivets,i have to to a couple of places that have said they are 4.8mm not 5mm is this right or do they have to be 5mm

For the difference use either...

You should get a box of them in the deluxe kit,
I did.
Steve.

only getting starter kit dont think you get them with that

I really wouldnt worry, 0.2 mm is nothing. When you start building the car you will find you worry about little things like this less and less.

just make sure you use a 5mm bit. it'd be a pita to have to ream them all out a gnat's bollock hair if the 5mm rivets wont fit in a 4.8 hole!

sorry if that was obvious
tom