Hello Jack,
I just had a telephone call with the EPO - they confirmed the proceedings in your case, just forget my comments above.
I found some details, which might be helpful, maybe you have a a look at
http://documents.epo.org/projects/babylon/eponet.nsf/0/7c5ef05581e3aac0c12572580035c1ce/$FILE/applicants_guide_part2_en.pdf
which is the applicant's guide, see section E-XIII:
No supplementary search performed: EPO was ISA
437 Upon entry into the European phase the applicant must choose one
invention from those searched during the international phase by the
EPO as ISA to form the basis of the examination. If this requirement is
not met, the applicant will be invited by the examining division to
indicate which invention he wishes to pursue.
Supplementary search performed: EPO was not ISA
438 If after entry into the European phase a supplementary European
search is to be performed (EPO was not ISA), it will be carried out only
on the invention or group of inventions first mentioned in the
claims (as possibly amended upon entry into the European phase),
regardless of whether an ISR was drawn up in respect of that invention
in the international phase and regardless of any earlier findings as to
unity of invention in the international phase.
439 Although the EPO is in no way bound by the opinion of the ISA on the
question whether the application meets the requirement of unity, the
EPO will, given the fact that the practices of the ISAs are based on the
same Guidelines (Chapter 10 of the ISPE Guidelines), in many cases
share that opinion. Therefore, where the ISA considered the requirement
of unity not to be met, the applicant is advised to amend the
application in due time in such a way that the invention on which the
applicant wishes the supplementary search and the examination to be
based, is that first mentioned in the claims.
440 If a supplementary European search report is to be drawn up, the
invention that was the subject of the supplementary European search is
the only invention that can be examined (see points 435-436). If the
applicant wishes a different invention to be examined he will have to file
a divisional application.
Best regards
Patmatt