During the mid 60s, a new No.1, known as the T63 was introduced for ORs.
I had to buy mine for AOC's Parade at Coningsby, 1957.
It cost £7+, a lot more than the quarterly Clothing Allowance. If your allowance went to Zero, you made up the differencce from your pay.
By the early 60's surely recruits were issued with them?