Thanks for all the input, it's really helpful. The booking is on an older style Amex241 by the way so I doubt going on Aer Lingus via Dublin would be possible, essentially I've got a free transfer to any BA or AA flights ( that's how I understood it anyway) due to the original cancellation, they notified us a long time back but we've been waiting to see what routings might open up. I think we will go for a routing via CLT if possible or do the early LGW one.