Well, I hate to say this, but...I actually find this guy easier to understand than some of the heavily-accented "British English" that I have heard. He actually has a wonderful voice, which is sorta wasted on all those clicks and pops and hisses.
I watched a hunting show recently that was following along on a Red Stag hunt on the Scottish moors; I thought it was pretty funny that there were subtitles along the bottom to translate the guides heavy brogue. And I have been on a couple trips to Newfoundland and often wished for a translator while there.
We had a wonderful gent with a heavy Newfie accent on the last jobsite where I worked, and he was challenging to follow at times. For a long while he and I were partnered up on a 2-man project that gave me a chance to learn to decipher him a bit. One time the foreman came by and asked how we were doing. My buddy jabbered on amiably for about 60 seconds or so; the foreman listened politely, with furrowed brow, nodding a few times, and then looked at me. I said "We're doing great" at which point he gave us the thumbs-up and went on his way.
The two of us laughed so hard and for so long that we couldn't breathe.
I must admit, it doesn't matter what grasp of the English language you have, there are parts of Scotland, and Ireland too for that matter, where the Scottish and Irish accents are totally indecipherable.