MadaboutKitcars

The high build primer is likely a 2K polyester.

There are also many single pack enamel type alkyd yacht paints which have GRP primers (I suspect the craftsmaster to be similar even though they don't sell it specifically for GRP) - international Paints, Teamac, Epifanes, Hempel are brands that spring to mind, and their topcoats are very good.
It's (as previously stated) mostly in the prep, cleanliness and swift application!

Thanks guys - although I spoke to a paint shop today that seemed pretty reasonable costwise - so I may go with them instead - still deciding on the pros and cons

Have they seen your car and is the price just for spraying?
If they need to do some prep work first then the costs can escalate.

I told them I'd try and do the basic prep work - filling and sanding etc

On that note - anyone got recommendations forthe best filler to use on fiberglass?

Are your panels rigid or do they flex?
Rigid- then most fillers will adhere to the keyed surface.
Flexible- try to use the filler used on plastic bumpers.

How much filling do you think you have? The panels look good in the pictures

They are pretty rigid but flex if you push them obviously, so maybe it's best to use the flexible stuff - what is the bumper filler called - do you know?

I think it was just alled Flexi filler but isopon do a bumper filler.

I have a local paint shop that I buy my consumables from.
Leonard Brooks, ive used them for 20+ years and his advice has always steered me right

Cool, thanks

Found this stuff on amazon - seems about half the price of the isopon stuff - anyone tried this stuff? - Silverhook BIG31 Big Boy Plastic Flexi Filler

Roadster - is that Brooks in Harold Wood by any chance?

There were a couple of articles in Complete Kit Car last year about painting with a brush using marine enamel.