You should only overtake on the right of any vehicle unless there are two or more lanes coming up to traffic lights.
I don't know about Jersey but you are definitely wrong according to the UK Highway Code.
"72
On the left. When approaching a junction on the left, watch out for vehicles turning in front of you, out of or into the side road. Just before you turn, check for undertaking cyclists or motorcyclists. Do not ride on the inside of vehicles signalling or slowing down to turn left."
163
stay in your lane if traffic is moving slowly in queues. If the queue on your right is moving more slowly than you are, you may pass on the left.
151
In slow-moving traffic. You should
be aware of cyclists and motorcyclists who may be passing on either side"
Given that many roads now have cycle tracks, it is the norm for cyclists to pass on the left, with all the above caveats about being aware of traffic that may turn left in front of you. When there is a dedicated cycle track, it is the car driver's responsibility to slow down and make sure they are not cutting up a cyclist. Believe me, in Holland you would be arrested if you hit a cyclist while turning left across a cycle track. In fact, the driver is always in the wrong if they hit a cyclist in Holland.
In addition, the proliferation of advanced stop lines implies that cyclists have to be allowed to get to the front of the traffic, for safety reasons:
"178
Advanced stop lines. Some signal-controlled junctions have advanced stop lines to allow cycles to be positioned ahead of other traffic. Motorists, including motorcyclists, MUST stop at the first white line reached if the lights are amber or red and should avoid blocking the way or encroaching on the marked area at other times, e.g. if the junction ahead is blocked. If your vehicle has proceeded over the first white line at the time that the signal goes red, you MUST stop at the second white line, even if your vehicle is in the marked area. Allow cyclists time and space to move off when the green signal shows."
Sixty pound fine for anything but a bike deliberately stopping on the ASL area (apart from the above condition, when you have no choice), although most taxis and buses seem to be unaware of that fact, along with the police.