Wifi Problems Still

[Slobbo]

Well. After 18 months, 1 laptop replacement and weeks at Apple. I am still having problems with the Wifi. Every other device/computer works perfectly so it isn't the Access Point. It fails on every access point I try and I have tried many. Basically the wifi drops and the laptop cannot see any access points to connect to unless you shut the lid and open it again. The sleep signal seems to reset the wifi and allow it to connect again. If I turn off the wifi from the menu and switch it on again it won't connect again. It either has to be a restart or a sleep to reset the connection. The following is a snapshot of the messages at the time it fails.

01/08/2011 15:30:49 kernel AirPort: Link Down on en1. Reason 4 (Disassociated due to inactivity).
01/08/2011 15:30:49 kernel vmnet: bridge-en1: interface en is going DOWN
01/08/2011 15:30:50 configd[13] network configuration changed.
01/08/2011 15:30:50 vmnet-bridge[119] Dynamic store changed
01/08/2011 15:30:50 vmnet-bridge[119] Failed to read SCproperties for key: State:/Network/Global/IPv4
01/08/2011 15:30:50 vmnet-bridge[119] Stopping bridge for: en1
01/08/2011 15:30:50 apsd-ft[245] <APSCourier: 0x101809a80>: Stream error occurred for <APSTCPStream: 0x101a21e30>: Error Domain=NSPOSIXErrorDomain Code=57 UserInfo=0x101a22a80 "The operation couldn’t be completed. Socket is not connected"
01/08/2011 15:30:50 apsd-ft[245] <APSCourier: 0x101809a80>: Stream error occurred for <APSTCPStream: 0x10180f320>: Error Domain=kCFErrorDomainCFNetwork Code=2 UserInfo=0x100637970 "The operation couldn’t be completed. (kCFErrorDomainCFNetwork error 2.)"
01/08/2011 15:30:51 kernel vmnet: VMNetDisconnect called for port 0x18a95c00
01/08/2011 15:30:51 kernel vmnet: Invalidating peer info for hub: 0, port: 0
01/08/2011 15:30:51 kernel vmnet: bridge-en1: filter detached
01/08/2011 15:30:51 kernel vmnet: bridge-en1: down
01/08/2011 15:30:51 kernel vmnet: bridge-en1: detached
01/08/2011 15:30:51 kernel vmnet: Freeing hub at 0x1cd4a000.
01/08/2011 15:30:56 Firewall[98] krb5kdc is listening from :::88 proto=6
01/08/2011 15:30:56 Firewall[98] krb5kdc is listening from 0.0.0.0:88 proto=6

This can occur 10 times in 10 minutes or 2 in 2 days. If I use a 3G dongle or ethernet cable no probs.

I recently cleared and regenerated all the system caches using Tinkertool System and it seems to have helped. This is really affecting my work. Is there any increased debug logging I can switch on for the kernel or network?
Any ideas about a fix? I have tried changing WEP/WPA/WPA etc. and Channels and speeds. Nothing helps.