Ha, I should have known my post would be divisive!
For me, one of Rapha's main differentiators is that they will replace or repair your kit when needed. That's the reason I bought the shorts. To think that I then wouldn't make use of that guarantee when needed is an interesting perspective. I agree that 85 quid for 3 years of bib short is absolutely acceptable. However, when nothing else is wrong with the short other than the single see-through panel, I also think it's acceptable for me to make full use of their guarantee and ask for a repair or replacement.
I wouldn't have asked for anything if the shorts were Castelli, for example. Equally, though, I've many cheaper pairs of bibs from other brands outlast these ones, so I don't agree with those saying that expecting that sort of life is unreasonable.