I am seeking advice re using oil based undercoat as top coat for internal woodwork. We want a flat finish on our white internal woodwork. Hate using water based paints. Tried satin and eggshell oil based, but even eggshell is a little too shiny. Recommended to try Johnstone's flat oil paint over undercoat (Leyland Trade oil based undercoat from SF). The latter is easy to apply and easy to lay off to lovely smooth finish. Whilst pleased with the flat oil topcoat, I found it a little more tricky to apply and lay off. So I actually prefer the undercoat to the top coat. It's also a lot cheaper! Could I simply use 2 or more coats of Leyland oil based undercoat? Is there something extra in the flat oil paint that's essential to make it resistant to marks and knocks, and fade resistant? Any advice much appreciated!