If you haven’t had your second jab, it’s worth trying to see if you can rebook it - I know that it’s pretty easy to get a second AZ jab accelerated, even if you’re below 40. Go onto the NHS vaccine booking site, cancel your appointment and then rebook it. Some people I know succeeded in getting a considerably earlier appointment. I had Moderna and doesn’t look I can get my second prior to 1st July, most like due to low Moderna supply.