We managed to flatten out most of the orange peel effect this morning.
We tried 240g glass paper but it was not working well.
We then had a go with a green scotch pad.
This worked well.
We ended up putting a pad on the electric orbital sander.
This flattend the rough areas quickly.
2nd topcoat applied.

After a night time drive through Cambridge, Sirenia is now tucked away under my bed again.
Looking quite shiny
 
There are a few areas that could be better but it will have to do for this year.