First couple of months seatpost never slipped, now every ride is slips. I have tried the carbon paste and electrical tape but still slips. Only thing I can thing of now is to wet sand the clear coat to rough it up a little, any hints would be appreciated.

I'll ask the obvious, is it torqued to spec?

Yes!

Try using some hair spray to fix it.

Have you checked for any cracks. There will be a reason why it's started slipping.

Assuming everything is fine and no cracks etc......
On a LOOK 585 i had the same issue, tried everything, mine even went back into warranty for a new post, it was fine for a while and then started to slip again!
In the end i got a Miche x seat clamp from PBK, which is designed to accept a higher torque figure.
http://www.probikekit.com/uk/contact-po ... clamp.html" onclick="window.open(this.href);return false;

i found i didnt have to go to 10nm max 8nm was perfect.

With hairspray is there any creaking noises?

Why would there be any creaking? hairspray would just be an extra degree of sealant.

because it's like like glue and dries out, it's not a lubricant!