2 Litre Saloon Flywheel Damper

[Gordon Rainbird]

I am trying to remove the flywheel damper from my 2 Litre Saloon.
   
   The nuts have loosened, but the bolts turn as the nuts turn.
   
   I can get two fingers behind the damper to feel the bolt head, but cannot grip it and don't have a spanner which will fit behind.
   
   Can anyone recommend a tool which will do the job, or do I have to modify and existing spanner? Or is there a 'knack' that I haven't thought of?
   
   Many thanks
   
   Gordon