madmum I know it’s easier said than done but just take a breather - you seem very stressed out! I wouldn’t worry about ringing universities. He’s well within the deadline - some people submit as early as September, others wait until July but they’re all considered equally. Get him to press send on his form (which means it goes to the school and they can add to and edit it) and then find whoever coordinates UCAS to let them know. Then I’d give them a few weeks to sort references and send off, if it’s not done a fortnight after he’s sent it then I think start chasing them.
And the number of applicants per places isn’t as scary as it sounds - the rate of offers to applicants will be much better. I remember DD came back from Warwick’s open day with a figure like that, but in reality many of those would have an offer but wouldn’t put Warwick as first choice. Unis always give our way more offers than places 