Composite rank braid was introduced in 1972 and on blue uniforms and shirt rank slides, it became de facto after about 1975. Because of the way it is woven, it can be sewn on the uniform inside out!! Many variations have appeared, such as the composite braid being sewn onto a shirt coloured or DPM backing which then forms a slide for the uniform. As an aside, I did once find it necessary to explain to a flt Lt that his rank slides, backed on DPM, ought not really to be worn on a wedgewood blue shirt!
As for No: 5 mess kit, individual bands of - supposedly - gold lace are the norm but of course unless one's rise is fairly meteoric or the mess kit is kept in the dark, the new braid is obviously likely to be a different shade of gold and now is more likely to be artificial gold lace. The secret is to have all new lace and then hang the mess kit jacket in the sunshine to 'weather' - it is then suitably matured so that one does not appear to be a newby! (insert here a caution about it raining).
On the No: 6 (tropical No: 1) the shoulder boards, which used to be rigid, are now just floppy uniform material and the rank badges mostly composite. The 6A and No: 8 still use blue shoulder boards with individual bars of gold lace.
However, ladies and gentlemen, whatever you wear and however you wear it, do so with pride.
Old Duffer