You are mixing a few things up there.
Inventor != applicant:
Inventor is the person that invented the invention, applicant is the person that applies for the patent and therefore is the owner of the patent (e.g. the employer). The compensation for the inventor has to be agreed upon between those two.
In your case that would (probably) mean that the ...
The patent office will only communicate with one party. In this case it would be the attorney/agent with the power of attorney. In the case of multiple inventors they can designate one if them to speak for all. I’m sure you can see the reason they need to only deal with a single party.
To find out EP applicant or inventor or representative communication details you need to visit EP Register.
search european patent in http://worldwide.espacenet.com/?locale=en_EP
access EP register tab on biblographic page
steps are compiled in following image
To get in touch with the inventor or applicant of a European patent or application you need to accesses the European patent register.
After which open the EP register and click on advanced search https://register.epo.org/advancedSearch?lng=en
Enter EP1870511 in the publication number bracket and you’ll ...