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Mike is absolutely correct. Whenever you are changing your website and the URL's are changing you should always make sure 301 redirect the old URL to the new one. Saves all the hassle of finding the links.

Thanks Mike - that sorted it! Cheers

SEMRush is exactly what you are looking for. Just plug in a URL and you will see the top organic keywords as well as PPC keywords any website is currently ranking for, the number of searches each month and the estimated percentage of traffic any particular keyword is responsible for generating. It's very useful to quickly find out the keywords your competitors are targeting and ranking for, as well as on your own site to uncover keywords that you may be ranking 19th for that you weren't even aware of.