There is nothing special about metric bolts used in the Lotus cars, unless they are non-standard size. Therefore, such bolts could be obtained from a reputable supplier.
On the other hand, be VEEERY careful when it comes to suspension bolts!!! Hardware store bolts are suspect.
So, please, check the number on the head of the bolt, it should be 10.9!
The most important part of the bolt is the grade. Metric grades are 8.8, 10.9 and 12.8. The grade corresponds to the strength of the bolt and the steel used. Generally 8.8 or lower should NOT be used, unless it is used to bolt a cup-holder and then you would probably snap it
12.8 is very strong but maybe brittle, so use with caution.
The threads should be rolled and not cut, although this is hard to tell. The thread should not run all the way to the top, it causes a stress riser under the cap. Usually metric thread does not run all the way to the top. The thread should engage in the nut or in this case the hub to the depth of at least 2x the diameter, so for 10mm bolt it should screw in 20mm or 3/4", minimum. (Aircraft bolts come with exactly the amount of thread you need that is why there are so many kinds).
Any kind of plating weakens the bolt. Stainless is generally not graded and should not be used. Titanium, bolts are not graded and are weaker then steel. There are aluminum bolts made of 7075, they are also not graded.
Metric bolts are sized by diameter, length and thread pitch. M10x80mm is 10mm diameter and 80mm length. 10mm is about 3/8". The problem with metric bolts is thread pitch. There is .75, 1.0, 1.25, 1.5, 1.75 and 2.0 mm pitch. Some is really hard to find in North America.
Bolts should be bought from a reputable supplier, so you can rely on the grade stamp. If other people are trusting their heavy equipment with it, you should be OK.
P.S. Only useful non-metric grade is SAE 8. There is only coarse and fine pitch for every diameter. There is Grade 9 or L9 sold, but it is not official SAE, although the specs look good.