A bit of useless info for L1A1 owners
In the tropical Far East/Malaya area we used to encounter severe rusting inside the 'RING, retaining, handguards'. If not kept in check, it would quickly rust through. When it did, or got near to, we would replace the ring BUT before you could, you had to unbreech the bloody things and with the L1A1, it was a bit of a precarious business because if the body wrench slipped just a tiny bit, then it would distort the body ........ never to be straightened again!
To get over this at Field workshop level, instead of unbreeching, we would cut the old ring off. With the new ring, we would snip it across the top, narrowest section, open it so that it'd JUST slip over the barrel at the gas block end, then braze the two snipped ends back together.
If you cut it with a hack-saw instead of snips, the radial diameter was reduced and made the handguards too tight (Ok, slim the wood down if you did....).
So, if you have an L1A1 that has the hanguard retaining ring brazed together at the top, under the gas cylinder part, then you know that the rifle has been to Malaya, Hong Kong or Singapore and been serviced at one of the British/New Zealand or Australian field workshops there. If only it could talk..........