Thanks Beachside, but I've tried White Knight.. twice.. and couldn't get the finish to look right.. words can't describe how frustrating it is to sand, prep, paint, look bad, sand back, paint again, look worse.. (30 panels).
Keen to try a matte finish this time - just trying to work out the polyurethane part.
I have used the tile paint on shower fibro walls (can't remember correct name). With good preparation with wet and dry (wet) and rolled undercoat, light blocked down and rolled 2 top coats it came out like a spray job. You must be doing it the wrong way ....no offence, but you may not realise. The White Knight laminate paint (which I assume you used) is probably similar to the tile paint - it has good flow, nice to use.
I don't know what surface you have - timber will be different to laminate, but generally speaking make sure the surface is rubbed back with something fine like 280 (using something courser first if necessary) and depending on how worn the paper is, then undercoat, give very light rub back and remove any dust in paint so that it is like a dull mirror finish, top coat and when dry lightly rub back again as before, then top coat again. I have painted many things like this from house doors to desks, in paint, varnish/polyurethane.
The roller is the important part, I use a thin pile
mohair (not wool) roller for gloss. I have used Rota Cota in the past. I have tried other roller materials with inferior to horrible results. Foam for example will leave bubbles. After rolling the piece I go over it again with no pressure, just the weight of the roller. You should not be left with much orange peel at all but if you do let the paint dry another few minutes and roll
with no pressure again - this will flatten out the orange peel due to the paint being not quite so wet. It takes a bit of experience, but by the time you get to the top coat you will have it right and sanded any mistakes away. Block down with a cork or rubber block - the rubber ones are ideal for wet rubbing. If you can't find one in the paint section of the hardware try the auto paint and panel repair product section. Use some soap (cake) on the wet and dry paper to make rubbing easier (just one rub across the soap now an then) if rubbing wet, and clean with a wet rag to remove build up of paint. Make sure you wipe down surface well to remove any soap residue.
I like using a roller but I have seen bathroom tiles painted with a brush. I have a good eye for detail but I did not pick the tiles as being painted straight away. White Knight flows out nice when drying, not like a lot of modern enamels which dry too quick.