Roundabout Lane Question

Just had a mini mock test with my dad, remember coming on this route in the first test (don't think I had an issue in the test first time as I had to use the 1st exit), was just debating with my dad about which lane to use on the roundabout.

Approached this roundabout to turn right (3rd exit); marked 'Central London A40'.

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It basically has two lanes leading up and on the roundabout.

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Basically what my dad is saying is stay in the left lane even for the 3rd exit because it's easier. He says no need to use the right lane even though it's the conventional way to do it. Do you agree ?

Basically what he means is, before every exit the left lane splits with one lane for exit and other to continue around the roundabout.

Image may be NSFW.
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Image may be NSFW.
Clik here to view.

Should I just stay in the left lane to turn right on the roundabout to save myself the hassle of changing lanes and that ?

Link on google maps: https://www.google.co.uk/maps/@51.54...2!8i6656?hl=en

Cheers