Roy&Peter;
I am not quite sure where on the centre seat your anchor points are.
I guess on the vertical surfaces.
The GRP on the seat is quite thin, so in itself not strong enough. However providing you can distribute the load with appropriate timber backing pieces expoxied in place then it would be ok
For the genoa halyard this might mean something over the entire underside of the sea.
On the toe straps – which anchor point gives trouble?
Hope that helps