try calling the music dept on Monday - you can buy them at any time during the term so they might be able to do an 'emergency' order
re the base layer - DS persuaded his Dad to order set for him because I was away when the letter came home. Seems very expensive to me. However I have spoken to DS about it & he accepts that last season was especially cold but says whatever level you are at it really can get very cold (he plays for his year's second team) and he is convinced by friends who have them that it will make a difference.
I can see that while those who aren't in the team may not get so much use from them they may appreciate them all the more if they are less vigorous in their participation in the lessons!
Having said that my eldest DS survived his time at the school without - it may have helped prepare him for those mornings where he had to break the ice on the Cam at 6 am so they could get the boat out for an outing