I've had to remove the headling in the locker to fit new chain plates, so no I am left with bare GRP. What sort of paint can I use to tart it up and does it need priming first?
Flow-coat, it's just resin with a pigment added, used on the interior of most yachts for years, just wash the area clean then give a light sanding to remove any loose strands. apply with a brush like paint but a bit thicker.
If yo have any left over it will help protect the inside of the anchor locker.