From Jull’s letter, it is interesting that they dated each graphite pellet twice. I previously thought that they had obtained two pellets from each subsample. If the pellets were only four, and not eight, then the weight is compatible with about 1 mg for pellet and it is quite possible that they dated only two quarters of the total sample.
The results for each of the eight measurements are known (they were published by Remi Van Haelst).
As to Zurich, it was Bonnet-Eymard, I think, who said that they also had kept a spare fragment, but without a proof as far as I remember.
In the website of ETH Zurich (the Institute were the dating had been done) there are the photos of some of the subsamples, but not all. I have tried to reconstruct the jigsaw puzzle of the three fragments that are shown for the first half of the sample but have not succeeded. Any body will try? http://archiv.ethlife.ethz.ch/e/articles/sciencelife/turin.html
But for Zurich there is another problem. Two unpublished sheets of data, presumably a first version of the radiocarbon results, have appeared in an Italian documentary (La Notte della Sindone, The Night of the Shroud). Some of the results for Zurich are different from those that were published in Nature. I have published an article about these data in January 2013, but it is in Italian. I have already done an English transltion and it will soon be published on the internet.
Three days later the English Version of “Two sheets of data of unknown origin with presumed results of the 1988 radiocarbon dating of the Shroud of Turin” was online
In a separate email to me, Gian Marco Rinaldi writes:
As you will see, two data sheets have surfaced which are analogous to Tables 1 and 2 of the 1989 Nature report with the results of the dating but contain some discrepancies with respect to the published data. The discrepancies concern the Arizona data and especially the Zurich data. There are no discrepancies for the Oxford data.
The two data sheets have been shown in an Italian documentary, "La Notte della Sindone", without any comments. I have been in contact with the authors of the documentary, Francesca Saracino and Paolo Monaci, and have asked them about the provenance of the data sheets. Until now, it seems that they are not willing to provide any information. I think that they do not want to disclose the identity of the person from whom they have obtained the data.
Therefore I do not know if the unpublished data are "real" or have been invented by anybody for whatever reason.
You will see that, lacking any explanations, there is ground for suspicions about the conduct of the radiocarbon dating. In particular, for Zurich one might guess that in their second cycle of measurements the results for all the four samples (Shroud and controls) turned out to give younger ages with respect to the first cycle, possibly for a systematic error, and the measurements were repeated, if a portion of textile had been saved, or the results have been somehow altered or corrected in the published version. I do not myself claim that there have been any irregularities, but I think that it would be appropriate for Zurich to provide some explanation.
Already in March last, I had sent the manuscript of this English version to the authors of the 1989 Nature report, that is to those who are still alive and for whom an email address was available. Several of them have replied but had no relevant infomation to provide. In particular, I had written to Willi Woelfly and Georges Bonani of Zurich but they have not replied.