To confirm Z-M's information:
"The High Commission of India, London and Consulate General of India, Birmingham and Edinburgh have outsourced their visa services to the external service provider M/S VF Worldwide Holdings Ltd. All applicants, other than those seeking Emergency Visas or those holding UN/Diplomatic/Official passports, are required to fill the valid online visa application form through the authorized website (www.indianvisaonline.gov.in) and lodge their applications with our sole service partner M/S VF Worldwide Holdings Ltd. For more information please visit
http://in.vfsglobal.co.uk. High Commission of India and the Consulates will not be responsible for transactions made with any other websites or agents"
https://www.hcilondon.in/pages.php?id=28
The Indian High Commission have only been using VFS Global since 1 March last year. Other countries (such as Russia) have used their services for far longer, so they're a well-respected organisation.
See also:
http://www.telegraph.co.uk/travel/destinations/asia/india/articles/Tourist-visa-applications-to-India-what-you-need-to-know/
There are visa centres in Goswell Road (EC1) and Hounslow as well as Paddington.There are also 11 other centres in the UK:
http://www.vfsglobal.com/India/UK/contact_us.html#1