What I do is strap my clubs in and use 2 or 3 beach towels (not that anyone will need them this time of year) around the head of the clubs and use an external strap to tighten them, not had a problem with it and the weight never goes over 25kg even with the Mizuno which is under for Jet2 and Ryanair.
One word of advice though, if you are going to Spain bring everything you need, they are total rip offs in regards to golfing kit and balls, one place wanted €38 for a dozen Callaway big berthas!!! I also saw in a shop a driver worth (forget which one) £200 over here priced at over €400!!
I recommend the Srixon bag for protection, mobility and value it also comes with a carry case for itself for storage.
£24.99 is a bargin for a quality flight bag.