I'm planning to go to the UK to visit friends and also to take the International English Language Testing System (IELTS) while I'm there. What sort of visa should I apply for? General visitor or business visitor? Also, I was in the UK till December 2013 on a business visitor visa which I extended in the UK twice. Will it pose a problem for my visa application now? It's been 5 months since I've been back home.
I doubt you'll find an official answer, since this isn't one of the reasons listed on the Check if you need a UK visa page, but since taking a test is a) a perfectly legitimate reason to visit, and b) not work or business, the general visa seems more suitable. This is doubly so since you're also visiting friends.
Since you have been away for a long period of time and have a good reason to return, I don't see why you would have any problems getting the new visa. As always, any proof you can offer that you are planning to return back home (job, property, family etc) is useful though.