Follow up
By Whatplant
United Kingdom 
I posted the following question a few weeks ago and had two quick and helpful reponses asking for a picture.
"I have a deep purple plant which has osteospermum type flowers but almost holly shaped green leaves. can anyone identify it and if possible advise on aftercare. It is still flowering but is looking very straggly and I wanted to know if it should be cut back" -
finally here is a picture which I hope sheds some light.
Many thanks to Spritzhenry and Andyottley
25 Nov, 2008
Answers
Cut it back and mulch around but not covering the plant. You could try layering some non flowering shoots.It is an Osteospermum.
26 Nov, 2008
Yes sorry my info not clear, wyeboy is right you don't want to cover the plant with mulch, but offer protection to the roots as they can be quite close to the surface of soil, but fleese will do not harm to the top of the plant if you are in a very cold area.
26 Nov, 2008
Yes it looks like Osteospermum to me, can't be sure on the vareity but not all are fully hardy, it does look like one of the more common ones that can stay outside, but i would'nt like to guantee it, you could remove all top growth and then provide a thick winter mulch, if you are in a cold area of the UK i would also cover with fleece, just incase.
25 Nov, 2008