The extant parish registers for All Saints, South Wingfield, only go back to 1585, though that is pretty impressive. By no means all registers have survived that far back.

If you have produced a fully documented, accurately sourced tree going back to the 16th century then you are remarkably fortunate. This is not something that the majority of English researchers can expect to achieve. But everyone has to accept that there is a limit to how much further they can pursue their researches without resorting to guesswork or "attaching" records from other people's (probably dubious) work.

Unless your ancestors were of the land-owning classes, it is highly unlikely that you will find any record of their names (let alone their relationships) except in parish registers. It is possible that your ancestor was born and married in another parish but the LDS have only filmed and indexed only a fraction of the registers for Derbyshire parishes. Obviously, you might want to pursue your research further by going through the early registers at the Derbyshire Record Office but the problem will remain that if you find a likely candidate for your Jarmani/Jermanus (bearing in mind that there were many alternative Latin transliterations of the name, as well as many English variants) it will be, effectively, impossible to prove whether you have the right one, given that the majority of parish records have not survived.

Sorry to sound so negative, but it is always better to be realistic.