Dear OP. Your piece is a little ambiguous. If is if £700 for five passengers, grab it will both hands. If it is £700 extra then it may not be worth the extra money.

However, have you looked at the fares from Gatwick. £234 return in CE is not bad at all. The seat comes nowhere close to a J seat on AA Domestic (even AA have now admitted that it's not F whatever they might call it). However the middle seat is unoccupied and my 6ft husband fits in fine length and abeam as I ensure that he does not beyond waist band 36.

Frankly the seat apart, I was very disappointed with the meal offerings on AA domestic, and the drinks were served any old how. Fancy serving Prosecco in a tumbler! You'll get Lounge access at LGW. I can't think of a single Lounge in Italy that comes remotely close.

Opinion varies as to whether it is worth it or not, but for full Tier Points and miles - and of course Champagne of sorts, I'm in.