I have a 2006 1.7 FRV. 

The hand brake lever is fully out and will only return a couple of inches, when released.

I have unbolted the assembly from under the dash, but there does not seem any access into the unit.

When releasing the handle the cable to the adjuster under the seat does not move.

Any ideas would be much appreciated

Not really sure about the FRV Hand Brake adjustment Dave, with my CRV the adjustment is made by locating the Hand Brake Adjuster assembly which is in the console box between the front seats , remove the bottom of the console box and the adjuster is there, it is done by screwing or unscrewing the threaded nut adjuster until the correct tension is obtained on the Hand Brake operation. This might help other CRV Owners but again not sure about this on a FRV, Sorry Dave.

Have you checked it out on You Tube. That might a good place to find out, If you do find the answer Dave please put it on the Forum to possibly help other FRV Owners.

Cheers Dave Hope you and your Family have a Happy and Safe Christmas