This guidance (see page 40) is helpful in challenging EEA marriage of convenience decisions from the SSHD:
If the applicant attends the marriage interview, you must consider:
• the answers they gave during their interviews
• the evidence that led to doubts about the reasons for entering into the marriage or civil partnership
• any other documentary evidence they have provided
You must assess where discrepancies occurred and consider if these outweigh the questions where their answers matched. This must not be based purely on the number of discrepancies.
You must take into account the personal circumstances of the relationship. For example, it may be reasonable for someone not to be able to answer detailed questions about their spouse’s parents if they have never met them but it would be reasonable to expect them to be able to answer basic questions
about them.