Interesting.
In my time as an armourer I don't recall ever seeing 'FTR' on an L1A1, not to say that it didn't happen.
We certainly saw a high turnover of rifles, the replacements being base workshop refurbishments, in BAOR anyway.
Unlike the Lee Enfield No 4 Mk1 and 1*'s that underwent FTR, which effectively upgraded them to different models, Mk1/2 and Mk1/3, the L1A1 refurbishment din't fundamentally change the weapon it only brought them back up to original spec.