Do you rely on branded keywords for which you arent the brand owner? Ive seen alot of movement for these kinds of terms recenty.

I do think a navigation restructure is the way to do it and a way to better focus your link juice. No following certain links no longer works for internal site links - Google see's through that now.

Instead of your categories nav including a/or multiple sub cat nav links (im guessing thats how it currently works) on every page, inc the sub cat links on the main cat pages not as part of the main cat nav e.g. dont inc red widget, blue widget, green widget under the main 'widget' navigation, instead add links to red, blue, green widget on the main widget page. Hope that makes sense.

You said you set up targeting for the UK so why are you concerned that it doesnt rank on Google.lk?

If you want to geo-target a website for a particular countries search results you'll find lots of good blog posts about how to do it right here on SEOMOZ. Aside from that heres a few pointers:

• You really need the country specific TLD or at worst a country neutral one e.g. .net. If you want to target the uk then you will do much better having a co.uk TLD. If you DO have a co.uk TLD this is the main reason why you dont rank in Google.lk.

• Ensure the website content is written in the language of the country you want to target.

• Try and attract links from country specific tlds e.g. if you want to target google.lk search results try and get links from .lk websites e.g. website.lk