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I am not from that industry but in my opinion you are along the right lines, London Digital Marketing Jobs seems like a good choice, To back this I would take a look at the Bing Webmaster tools if you have them setup ? They offer a wealth of keyword information that google no longer offer, even if it is a separate search engine personally i would expect search trends to be very similar, Any chance you have an adwords account ? The keyword tool does the job well , www.google.com/sktool/ Also try Ubersuggest for Google suggested results , http://ubersuggest.org/ If you do have Google Adwords it is an amazing keyword resource by bidding on general/phrase match keyword, once you have some click data, mark your keywords and look at the keywords search terms selected data, I then disallow any search terms we don't want, Using this we have collected a lot of keyword data, I hope this helps slightly James