Well I reckon Mark should have a go. If he goes to one of the big Hire Centres, he can rent a router and a thing called a worktop jig. It's a template thing with lots of holes and cut-outs for different jobs. One will be for the scribe joint you need. It might have instructions with it. If not, there's probably a Youtube showing how it's done.
Check out the Youtubes first to get an idea.
The best part is that he can practise on one end while the top is still in one piece. If it doesn't work, he can move along and try again. As soon as the cut is right, then cut the other end to length..............
Tell him I said he can do it :o)