1. My old waterproof jacket probably is waterproof. After our episodes in Spanish weather last year, I was soaked to the skin each time we stopped. I now know that was due to having a buff around my neck that acts as a conduit/soakaway for the rain, transferring the wet from outside my coat to inside! I got every bit as wet today despite wearing a different, definitely waterproof coat and the buff!
2. The investment of £6-odd in an iPad-sized dry bag is already money well-spent.
3. Still need to sort a way of maintaining clear vision (Rain-X on safety specs' lenses?)