I can't see any comments on your website blog, have you deleted them. Where they have put " Carpet Cleaners Battersea " there is usually a link to their website, so they have a link to a carpet cleaning specific website and also a keyword/keyphrase in their link, this used to help with off line website optimization, but not sure if it is as important as it was, google keep messing about with things.You also have to be carefull not make it look like spam or they will just get deleted by the website owner/webmaster or do more harm than good on google, but there is a way of doing it to help with SEO, but like i said ,i'm not sure if it is as important as it was, i've not been keeping up with latest SEO techniques. I am not a massive expert in this area, but i did the same thing last year for one of my websites, i commented on blogs non-stop for about a month on any blog to do with " carpet cleaning ", carpets ", "cleaning ", "and any blogs in my area". I have to say it gave my website a massive boost in the rankings.