The markings are very confusing though.
At the 12s mark, you have the three lanes clearly marked, you were in the A61(S) lane. To your NS was the lane for the A617.
However, it looks like immediately after the turn for the (I presume) A617, instead of spiralling your lane to the NS, the lane for the A617 becomes the NS lane for the A61(S) - and the lane you were leaving is STILL the lane for the A61(S).
Without further footage, I'm guessing that both these lanes will go off onto the A61(S) & either filter into one lane or continue as a dual carriageway?
If there had been a coming together, your own footage would show you clearly leaving your lane & cutting the other guy up.
Can you link to the google map of that roundabout for clarification?