Whoever is behind it what they have clearly done is explore a route that isn't currently served, it might not be served for a very good reason, and thereafter they've done their sums realising that they need to charge a mega fare just to break even hence some bright spark has come up with the all business class nonsense.
'All Business Class' has been tried before and failed and precisely how business class can a Jetstream be particularly on a route where it's in the cruise for a little more than 30 minutes?
To operate UK regional to/from AMS it either needs to be on a KLM codeshare or it needs to be Loco!