As for undertaking vehicles - I do it all the time in traffic.
Me too. I can never quite reconcile the fact that anecdotally online a lot of people seem to say they don't undertake with experience on the road in where I very very rarely see cyclists in the line of traffic not undertaking where there's an opportunity to do so.
would check but I'm on the bus today and tomorrow 
silly to have a law to only enter from the right then.
