No need for new eyes just yet! That diagram shows how many different parts there are but does not show how many of each part you need. It is four of item 6, one of item 7, two of item 5. Item 7 goes in the middle at the back as shown and is longer than the other four.
You will get them much cheaper from a fastener supplier.
They are all 6mm screws and I will now go and measure the length for you.
Item 6 - 4 off -- 6mm x 40mm long socket head bolts. From the PDF Yamaha pt.no. 91314-06040-00
Item 7 - 1 off -- 6mm x 50mm long socket head bolts. " " 91314-06050-00
You might notice that the middle part of Yam part number gives a clue to the dia and length.
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Standard stuff, like those bolts, from an industrial supplier will cost about a tenth of the Yamaha (or Sutton) price. One near me in Lancashire
http://www.nutsofchorley.co.uk/ have always been happy to sell to me in small quantities when I call in but I don't know if they do mail order. Plenty on e-bay though.
Places like B & Q not usually much use for bolts on bikes as even if they have the size of bolt you want they are often made from a lower strength of steel.