When lack of unity is established, the sequence of the claimed (groups of) inventions will normally start with the invention first mentioned in the claims ("first" invention); see also B‑VII, 1.1 and B-VII, 2.3. In other words, as a general rule the division of subject-matter follows the order of appearance of the different inventions in the claims. The content of the dependent claims will be taken into account when determining the first invention.[Rule 64(1); Rule 164(1); ]
However, if the filed claims do not fulfil the requirements of Rule 43(4), i.e. if the dependency of the claims is not correct, the claims will be re-ordered accordingly before assessing the fulfilment of the requirements of unity.
Source: http://www.epo.org/law-practice/legal-texts/html/guidelines/e/f_v_4_4.htm
Date retrieved: 30 December 2018