Oxford street traffic regulations

Hi all,

for some reasons i have to go around that area quite often, i never understood whether motorcycles are allowed, from experience i think that during the night until 7am is fine, than there is a restriction…

At traffic light in front of primark, coming from Marble Arch, there is a sign of turning left, however sometimes the light just turns green without this sign…

Any of you know exactly what’s all about??

Thanks

I think the display at them lights say whether you can or can’t continue along Oxford St.
Can’t say I pay much attention as never really go that way.