This job would be straightforward for a kitchen installer. The corner mitre is no problem if you have the right worktop jig and router. If you are fitting it yourself, without this equipment, the only other option would be a metal corner jointing strip, which would give an inferior finish. All bare chipboard needs to be sealed before joining, as ingress of water would soon cause blown joints.
If you, or a fitter, intend to use 40mm rounded edge worktops, both ends would need to be routed square and finished with a glued-on laminate strip. The ends therefore would be square edged.
Also, I assume a new sink would be fitted, which would involve a sink cutout by jigsaw and, most likely would involve replumbing with alterations to the hot, cold and waste.
The other thing to check is the worktop depth. They come in 600 and 616, and 665 and 900 double post-formed. Length 3.6m and 4.1m. Plus you will need the laminate strip for the ends.