Stuart, you have my sympathy.. I backed the red 4/4 into the garage late one evening & scraped the rear wing on the brickwork.
Have to say I admire the way you're having a bash at some repair work yourself, after all if you have to pay someone to fix it professionally, you may as well have a play first.
I'm probably wrong, but shouldn't you feather the edges of the paint before you apply the primer..? It just appears that you'll be hard pushed to get that ridge edge down.