Steve - I don't want to give you extra work, but...
I made a separate bracket to support the tail pipes that tied back to the Spitfire wheel arches.
( You can see it in place in the photos above. )
I'm sure a variation on this approach could reach your fibreglass 'floor'.
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Mick - Bear in mind I only had 4 miles on the road when those underside photos were taken.
I dread to think what it looks like now after driving through the winter.
Cheers, Paul.
