Hello Eric, many thanks for your responses. I haven't shared a Notebook yet as the results I am attempting to match are, sadly, paper based and so you would not be able to see the problem I have in trying to match them. I can upload a jpeg of the original data though. Before I do that though, I am experimenting with the use of ` to specify desired precisions and starting with 30 which would seem to be double (not noble, sorry about missing the spell corrector blunder) precision on my Mac.
If I try this, I can set a high precision value for an estimate for FindRoot for example. The result returned, however, still seems to be machine precision. I guess that I am missing a step here and I would certainly appreciate further help.
I can build a stripped down .nb to illustrate my attempts if that would help but you may be able to suggest some more things for me to try first?
Many thanks, David