I'd go for the 11.05, but not check in and flex my options and take a later flight if the inbound was looking dicey. Anything beyond 30 min of delay and you'll be at risk of missing the bag drop cut off. Your only real problem then is if the door closes on time and you sit on the tarmac or in a holding pattern for a long time, and the cost of a one-way fare back to the UK somehow (on avios, as a walk-up on Ryanair if necessary) is probably low enough to accept the small risk of missing your return.