Surinder Singh route and the armed forces

I cannot believe this issue has never been tested, so I am hoping someone will be aware of the solution.

The claimant is a German woman who married a member of the British armed forces in 2007 while he was stationed in Germany.  They have a British child.  Last year they came to the UK.  They have now separated.  She has claimed JSA which is going to be reviewed in three months as DWP is taking the view that she is a job seeker.  She has also claimed HB and the Council is trying very hard to find an alternative right of residence she can rely on.

All I can think of here is the Surinder Singh route (family members of British citizens who worked elsewhere in the EEA before returning to UK), which would depend on the husband being regarded as a worker while serving in Germany.  I am very surprised that I cannot find any case law or discussion dealing with this.  For the purpose of benefits within the scope of the coordination rules the UK remains the competent state it seems; and since the employer is the British government and the employment was obtained in the UK it’s difficult to see how he has ever been integrated into the German labour market.  So the signs don’t seem promising.

Is there a definitive answer to this?

Thanks