Ofcourse he would be a fool to refuse such an opportunity on the M1. He isn't that fresh to MotoGP though, this is second or third season (can't remember ).
Don't get me wrong, it's all relative. I've tried some club level racing and can't imagine what MotoGP must be like - Ellison has talent I could only dream of, but so far I don't think he is up to MotoGP. He should be doing better on an M1.
His presence is not just down to talent spotting - I think another reason he got a ride was because Dorna like having some British riders. In my humble, anoying, drivelish opinion...