£300 is ok for an upgrade on East Coast flights, as a single traveler and if it’s not a problem in terms of cost then I would take it. I can’t say this will happen but you might get lucky and get an OpUp to Club. Theres 13 seats available in Club according to EF. If you don’t get an OpUp, I’d be happy in WTP either way. As I say it’s not something to bank on.