I believe the BCN-LGW delay can be blamed on weather but from then on it is an airline issue. I would keep pressing, iles.
Exactly. This is how I won my claim with LH when they tried to fob me off with an "unexpected technical issue". Through some research, at work, I was able to establish that the a/c had gone tech some 6 hours prior to my flight's dep time. Ample time to rebook me on a same-time alternative with a code share partner (and yes, there was availability on those flights). What they in fact did was to gamble that the a/c would be fixed in time and eventually only cancelled it at the STD with all pax at the gate. When I proved my case they gave up and paid up, reluctantly. End result for them was that not only did they have to fork out anyway, but they alienated a loyal and regular customer too.
One thing for sure is that ALL carriers will try and fob you off at least twice. When they eventually decide the battle is lost they will pay up but on the basis of a "goodwill" gesture and still without admitting any failure on their part. It's a complete farce! The whole experience has only made me even more determined to pursue a claim to the bitter end in any future event.