Front wishbone bolt size?

[Lesliehedley]

I was replacing the front springs on my 400SE and I managed to strip the thread of the lower wishbone bolt. I have ordered another one from Richard at RT Racing but when I tried to fit it, it didn't fit. Richard assures me that they should be 1/2 inch bolts, but the bolt that stripped appears to be 7/16 inch and longer than the bolt Richard supplied. The 1/2 inch bolt won't go through the holes in the chassis or the wishbone bush. Is anyone able to measure their lower wishbone bolt to see if they are 1/2 inch or 7/16? The 1/2 inch bolt also seems to be too short. My bolt is much longer. Richard's bolt wouldn't leave enough thread to get a nyloc on it. If anyone else has 7/16 inch bolts fitted, could you also measure the length please?

Did TVR alter the size of the bolts they use at some time? My TVR is 1990 so I would have thought quite late in the wedge line up. I'm puzzled.