Excellent write up Chris, really enjoyed reading about your adventures. Found it so entertaining I read it to the household, they laughed and understood your accounts. Sounds like you had a great shakedown run.
Re the overtaking, yes they do like to keep thier indicator on, although much time spent observing this has given some insight. It would seem that keeping your indicator on when in a queue of overtaking vehicles, signals to the vehicle in front that you wish to travel faster than he is and that once he has passed the slower vehicle he should pulling in to let you pass. It does amuse me watching it, and sometimes taking part.
As most of the autoroutes are duel carriageways there can often be quite a queue in the fast lane, the vehicles end up driving very close together when in this position. It's entertaining but brings an obvious risk, all involved are reliant that no one makes any sudden moves and that no vehicles suffer any failures. Fortunately I haven't encountered too close a shave when in this position, but on day two of a trip to Morroco in Northern Spain, as I approached a Spanish HGV it blew an inner driven tyre on the tractor unit. I managed to avoid the large chunks of tyre, mudflap, light cluster, wheel arch and chassis bracket that all came off in the process. The green truck fully loaded with gear and the tent on top handled very well as I swerved around avoiding the debris. Gave the HGV's even more room after that close call.
I must say that I haven't encountered the flashing lights from the vehicle behind when overtaking abroad, unlike the impatient soles we share this island with! I think the driving standard of overtake and then pull back in is the norm abroad, but I suppose our roads are a tad busier than theirs!
A shakedown trip is priceless in helping you workout how YOU will live out of YOUR truck when on the road. Where to put stuff, how to organise the truck, how to refine your routine, Steph and I have had many comments over the years about how swiftly we can make camp and be sitting down to dinner. It comes with practice and each knowing their roles. A well set up truck is a pleasure, when moving on each day you want to spend the least time making and breaking camp, and the most time enjoying your trip. On those odd days when things don't go to plan and you end up arriving at camp under the cover of darkness, eveyone needs to know where the kit is in the truck and be able to make camp as though its a natural reflex.
Looking forward to following your trucks evolution and the next adventure.