I went through Swinderby early 75 and ISTR having one shirt of the 'blue and white threads' variety, but with attached collar, which was the 'No1 shirt' and several 'No 2 shirts' in plain wedgewood blue. I was also issued a 'Hairy Mary' and 'wooly pully' though the HM was replaced with a 'Thunderbird Suit' soon after arrival at my first proper unit.
Of course this was some time ago so the memory is not what it was!