Although I took a £2 job to France, Mr Bunbury sold me his official vest just before the off, and it was a good buy. They are a simple construction but a good cut, and ths zip works - which is all you want in a gilet. The rear pocket access slits aren't really big enough, but you can hitch the thing up easily enough.
The weight was perfect for me. I only wore it at night, and you can always undo a gilet if you're too warm! So it does indeed form a handy extra layer, easily zipped/unzipped for long descents/climbs. (Gilets ideally have meshy backs, but never mind.)
But I have to say that the site of all those block yellow torsos at night did sadden me a little. It felt like a uniform imposed on us, like easily-mislaid
enfants. We lost the variety of club/country jerseys which helps make the event so rich. Our Audax England logos were sometimes visible from the rear, but only barely. Next time around it would be good to get gilets that are more meshy to the rear. Or something. (can I cut holes in an existing one? Not sure what the EN regs say ... )
If I'm going to wear hi-viz on the bike, I may as well wear something with bragging rights
EDIT: oh yeah; at the bike-check I told them mine was in my luggage. So noone saw it