Storage in the Falkland islands you say ... I would take that with a pinch of salt. The FIDF sold off their L1's in the late 80's (or early 90's) and replaced them with Steyr AUG's. So very long gone ... I believe they were all imported into the UK and virtually all deactivated.
If these rifles are in excellent condition, then they are probably ex UK war reserve pieces, or they have been refurbished by a company like LuxDefTec. I hear a number of ex War reserve L1's are still stored with dealers in Holland.
Very interested to see were they are being proofed, that might give us an idea...