Just got back tonight. To ease your concerns.
Chunnel :- As said already, easy once onboard, bit of a nightmare approaching from Canterbury end though due to road works etc. Self check in a delight. Kept the bikes back and loaded us last, same as return trip. Something to do with spacing on the train, easier for cars to go bumper to bumper. When you board there are two raised areas (Kerbs) on left and right sides, ride down next to right side then turn bike in and rest front wheel against raised area on left, bike straddling across carriageway, sidestand and first gear, sorted.
Hi-Viz vests :- Not one in sight.
French Police :- as above (Apart from P/port control). P/Port checks are done this side of chunnel, so arrival in France is just a straight drive away, no customs or anything. Same for return, done in france straight drive off in UK. What a good idea.