I am no expert but there is a "right to roam" in the UK which means that you can wander over any common land, moor land, mountain, heath or forestry commission land. However Agricultural land is a bit different and the best thing to do is to check an up to date OS map to see what rules apply. Otherwise, stick to footpaths and public right of ways.
It looks like a good training program to me. You might want to throw a longer slower run into your program in two weeks time just to keep the distance in your legs but other then that you look like you are rightly making speed/tempo work the focus of your training. Best of luck for the next few weeks
If I had seen this thread in the forums a week ago your experience would have been completely alien to me but the exact same thing that you are describing happened to me last weekend. I have always ran the morning after a big night out to clear a hangover but last weekend I felt the same sensation that you had happen to you. I started work on Monday morning and my heart on numerous times throughout the day would beat out of rhythm and sometimes would palpitate. After a quick Google search and a chat with a doctor pal, I think it could be a combination of alcohol, lots and lots of caffeine as well as exercising on a hangover. I didn’t drink any caffeine on the Monday following the weekend and my heart has been back to normal ever since. I am switching to lattes instead of espressos and will probably not do any intense triathlon or running training after a big night. Stopping the drinking is out of the question of course!