That "can't be bothered/bored with/just want my back pay" attitude is exactly how to get the best deal.......for the company.
You are NOW in a really good position to ask for a lot of things. Strangely you're not asking though. You are about to accept a worse deal than Balpa originally asked for. That is the product of 18 months of negotiating. What makes you think that the next 18 months will be more succesful? Sadly I think you are setting a precedent for future negotiations if you accept this offer.
Just to reiterate.
Flybe have just made their biggest profit ever, in the middle of a recession.
THEN! you can negotiate a proper deal
Are you implying that the current deal isn't a "proper" one? Yet you are still going to accept it?!