Flexi plus is not cheap, nor does it necessarily get you through the passport checks any quicker.
I maybe use the Chunnel more often than many bods, having used it six or more times in the last four months. It can be a lottery, but here are some basic guides.
A. They are now running more trains. For a while they were running two trains (sometimes, just one) an hour. Less trains, equals longer waits.
B. The longest delays are caused by cancellations (or simple postponement) of trains, due to technical problems. Obviously, if trains are cancelled, the queues build up much faster. The Chunnel is now over 25 years old and the infrastructure (particularly the rolling stock) is becoming pretty creaky.
C. The UK side (England to France) is generally fastest, unless:
i. You get some officious jobsworth at the checks. This applies equally to the the UK and to the French passport authorities but can also apply to the privately run ‘security’ checks, if your vehicle is called in for one.
ii. Sometimes the UK authorities run two passport checks on the way out (England to France); why, I have no idea. This adds to the wait.
D. Coming back (France to England) is generally slower, largely dictated by:
i. How many gates they have open.
ii. Demand. If you travel at peak times on busy days (amplified by holiday periods) the queues are longer. That rule applies to just about anything to do with travel, obviously.
iii. What speed the officials chose to work at. As a rough rule of thumb, the French officials are generally faster and more polite.
E. They have reconfigured the return (France to England) side, introducing a sort of roundabout / chicane, to bend the queues. This is in an attempt to prevent the queues stretching right back to the motorway, which was (obviously) dangerous.
F. Several years ago, I took up travelling out (England to France) mid-to-late afternoon, as the queues are shorter, as demand is lower. I also took up returning (France to England) at between roughly 10:30 to 11:30 local time, as again the queues are generally shorter. The possible downside, is that they have less gates open.
G. I have been through the passport checks in under 15 minutes and sometimes waited closer to a hour. That excludes the time spent:
i. Waiting the train to be called in the first place. There is little point arriving much before a hour before your booked time, nor later than say 30 minutes.
ii. Any wait having gone through the passport controls, generally dictated by how ahead of your allotted train you might have might have turned up. Contrary to rumour, they do not always allow you in ahead of your allotted slot, more often than not dictated by overall demand.
H. It pisses car drivers off, when bikermates jump the queues by pushing in. This is not surprising. Most often the most pissed off, is when a gaggle of up to 20 bikes, all travelling together, decide to jump the queue en masse (that’s French).
I. If you are unfortunate enough to follow anyone through who has no idea what they are doing, loses their passport or decides to piss about or just for some unknown reason alerts the officials to be cautious, then the time expands, obviously. This applies particularly to bods on motorbikes, who sometimes faff about as they are twats, without the slightest clue as to whether it is Christmas or Marble Arch. What to do with their gloves, where did they stash their passport, where is their entry number, what to do with their passport when it is handed back, what to do with the paper numbered ticket, once they have got it? To some, this is beyond rocket science. This applies to airports too and, to some degree or another, any form of entry or exit.
J. If you are unfortunate enough to be stuck behind a motorbike with very loud pipes, who thinks it is cool to blip the throttle every 20 seconds or each time they restart, it becomes very tedious. This applies particularly when exiting the train, as the doors do not open instantly, nor does embarkation commence as soon as the doors do open. Some cnuts cannot understand these two, very simple, facts. Nor can they understand that their noise and exhaust gasses travel backwards. But hey, that is bikermates for you.
Enjoy your Chunnel experience or take the ferry or go Scotland.