The centre lane is indeed the one that carries on and splits into two. The cyclist is in a strong primary, not even enough room for a car to come up his right side. The lorry doesn't come from the lane, he hasn't driven up behind him, that's where his friend is, so no reason for him to shoulder check there as he takes the right split as he knows the only thing behind him in that lane is his mate and there are solid lines next to him and his mate. The lorry driver actually crosses the solid right lines illegally, having realised his own lane is a right turn only and he wants to go straight on. Certainly a lesson to us all to expect the unexpected!! I hope they got the truck driver.