Orange peel paint!

Not knowing the exact procedure you followed 1st coat thinned that's correct 2nd and 3rd coat slightly thinned using a medium pile roller and allow at least drying time between coats I presume it's water based emulsion you used was it vinyl matt or contract matt or silk ? As contract emulsion does tend to create an orange peel effect especially if not dried properly between coats As for remedy there's 2 options completely prep the whole area to a smooth finish then Repaint or crossline then emulsion Hope this helps and good luck Regards Adrian Jenkins

i suspect you may have used a foam roller sleeve? these sleeves create an orange peel effect which is in some cases, desirable but obviously not in your case. a high quality medium or long pile lambs wool sleeve is the way to go with a high quality emulsion such as leyland super leytex. charge the roller generously and paint approx 1 square metre at a time between charges making sure to backroll the whole area, (rolling at 90 degrees on the second pass to the original pass).