Firstly, if Shoreham Airport were in Brighton then it wouldn't be called "Shoreham" ... Then one reads that it's actually to Pontoise, which is not a designated Paris airport, and it's to be operated by a 19 seater 'Puddle Jumper'.”
Agreed, the statement is vacuous nonsense. Still, good luck to them if (clearly it is a big “if”) they can make it work. If there were LGW flights, there would expect there to be no chance.
It is no more rubbish than those Ryanair claims that they invest 180m EUR and create 1000 jobs if they base a Boeing 737-800 somewhere in the wastelands. Usual marketing talk.