I have just noticed that the mobile version of my site is sometimes ranking in the desktop serps either instead of as well as the desktop site. It is not something that I have noticed in the past as it doesn't happen with the keywords that I track, which are highly competitive. It is happening for results that include our brand name, e.g '[brand name][search term]'. The mobile site is served with mobile optimised content from another URL. e.g wwww.domain.com/productpage redirects to m.domain.com/productpage for mobile. Sometimes I am only seen the mobile URL in the desktop SERPS, other times I am seeing both the desktop and mobile URL for the same product. My understanding is that the mobile URL should not be ranking at all in desktop SERPS, could we be being penalised for either bad redirects or duplicate content? Any ideas as to how I could further diagnose and solve the problem if you do believe that it could be harming rankings?

My client has a blog that posts information about products to support its ecommerce store. The blog's main purpose is to support the products listed on the main website, but it has become so strong that its posts sometimes rank in the SERPS in place of the website product page, which is undesirable. The blog posts always link to the product that they are supporting. Are there any other methods, other than doing a 301, that could help the product page to rank instead of the blog post?

I have an established website that ranks well in Google. However, I have just noticed that no xml sitemap has been registered in Google webmaster tools, so the likelihood is that it hasn't been registered with the other search engines. However, there is an html sitemap listed on the website. Seeing as the website is already ranking well, do I still need to generate and submit an XML sitemap? Could there be any detriment to current rankings in doing so?