New Plusnet user & Ubuntu 10.04

[#1]

Hi all, new customer here.
Previously I was using a Netgear DG834 router to manage the network at home, connected to it wirelessly were android phone, windows 7 laptop, windows xp laptop, and ubuntu 10.04 laptop.
Plusnet broadband went active tonight so I swapped to the supplied Thomson TG585 v8 router and went about setting it up. I'd hope to set it up the same as the old one, to - hopefully - minimise setup issues. However the router isn't quite as flexible (or perhaps it is but isn't as user friendly) as the Netgear so this wasn't quite possible - for example I couldn't set up my static IP addresses within the WLAN to the same as before, but have just changed these to new ones.
The main problem is I've got the windows 7 and windows xp laptop connecting wirelessly, and the android phone. But I'm having no luck with the ubuntu laptop.
When I try to get it to connect it simply asks for the wireless network authentication password, and then the wireless symbol on the desktop does it's little pulsing animation (as it does when trying to connect to the network).... and then this loops (i.e. asks for the password again) until it fails to connect and stops trying.
I've deleted the connection and added it again, but no difference.
In terminal typing 'sudo iwlist wlan0 scan' detects the network (if it is trying to connect to the network at the time). Typing 'iwconfig' does the same. If the laptop isn't trying to connect, then the 'iwlist' command does bring up details of the network but not the ESSID (the router doesn't broadcast the SSID, so I believe this is correct).
The laptop hasn't moved, so I don't think it's a wireless reception issue (in fact, I'm using another laptop near it now).
The SSID, password, channel and encryption method are the same as with the previous router - the other laptops connected straight away.
So as far as I can tell, the only difference is the router hardware.
Any clues to get my Ubuntu 10.04 laptop connecting wirelessly to the router?  What am I missing? It's late, and I'm wishing I hadn't started swapping everything over now! Many thanks....

[#2]

It is probably worth reading through the issues highlighted in this thread - http://community.plus.net/forum/index.php/topic,92497.0.html
My laptop is Ubuntu 10.10 and my current router is a DG834GT and it works perfectly.
I use the same Ubuntu machine for sorting out other peoples broadband and wireless issues, and have not had any issues authenticating the WiFi, using the "pulsing animation" - although I can't say that I have ever tried a Thomson router.
My impression from other posters in this forum, is that the Thomson router is not as good as your DG834 at anything,  particularly WiFi and holding on to your ADSL signal during bad weather.
I would recommend using your old router but with your Plusnet login info, setting ENCAPSULATION=PPPoA, VPI=0, VCI=38.
I would also choose to use DNS settings of 208.67.220.220 and 8.8.4.4, rather than get them "automatically from ISP".
If that works, you may still be able to return your Plusnet router so that you don't have to pay for it if you were to leave within 12 months, alternatively you could hang on to it as a backup if needed.
For what it's worth, I usually have the exact opposite problem, in that I have always found Ubuntu to be the easiest machine to connect wirelessly, and it is everything else that has some issue or another !

[#3]

Mod:note
Locked in favour of http://community.plus.net/forum/index.php/topic,101799.0/topicseen.html