wow, what cap and how did it happen? I've been really fortunate on my 08 as I have so many of the 2010 LR4 component upgrades on mine from the dealer before I bought it. Suspension, A-Arms, compressor, etc... Had a tail light issue and brake light switch problem but other than that, my Landy has been extremely reliable. Everything I have broken was due to my own fault except those brake switch issues which turned out to be just a bad switch and then non-factory brake light. Super easy fix!
Sorry for your gas tank problem, I would be curious to know how and what the fix was?