Warning triangles are a must for cars/vans etc but not bikes. Reflective stickers on helmets are supposed to be, but I've never seen enforced. UK sticker/s (not GB) are required
You must have CE-approved gloves, as in the label inside the glove has a readable CE mark. Fat chance for some of my pairs. Never seen it enforced, though.
I've done Switzerland a couple of time on a Multi v4 with full Akra system on it, and I've passed police on side of the road, boarder crossings and never any issues, just don't rev to the red line, keep it sensible, revs and speed. Riding like and idiot will get you pulled in any country in EU. Any way you want to take your time and enjoy the amazing views. And when you hit the Italian border, forget everything, they don't care, especially if your on a Ducati
