Garage door paint

[Buzz word]

As per bank holiday tradition I have been getting stuck into some diy. The job this weekend was to re paint the flaking garage door. It's a battered old door and not in the best condition but I don't really want to spend new door money really. Anyway the job went reasonably well apart from I don't really like the result at all. I used Bedic MSP smooth satin black to recoat after seeing it recommended and hammerite slammed. Seeing as it's water based it's gone and done what all water based paints seem to do and kept every mark from its application so the smooth finish is more like a hammered effect from the gloss roller. You can also see every roller mark. The paint is far too matte too so now it looks like a hammered blackboard and I hate it.
So does anyone either have a paint recommendation for a paint like the good old oil based ones that went on and smoothed out by themselves to look like glass or any tips on how to but water based paints on and not leave horrible brush/ roller marks everywhere?

[Buzz word]

I don't know if a B&Q exterior gloss will be ok. It may be now as the paint I have on will act as a primer but my door is galvanized steel so I leaned towards the more specialised paint so I didn't have to primer and paint.

I think it may have been that thread I saw it recommended on. It's probably just my weak painting skills especially with water based that lead to my problems with the look. Maybe thinning it and a few more coats would actually have it going on smooth. Gloss rather than satin finish may have been a better call and hidden some sins too. If nothing else it's played a part as a tough primer. It was blue before so may go back to that after seeing it in black.