Well our guy lasted almost 2 months. Think it overwhelmed him a bit even though we kept assuring him that nobody expected him to simply replace someone who has done the job for 20+years, it takes time to learn. But such is life.
And so we're back on the market looking for someone....
EDIT: July '18. Just an update, found someone new. Doesn't have the electronics knowledge we were looking for, but has a great mechanical mind, good common knowledge and a willingness to learn. So far so good.