apply now or later? 775 for 666 entry requirements?

I'm applying to KCL, UCL, Durham, Queen Mary, and either Nottingham or Bristol for law.
My predicted is 775 with 41points in total, and this result is eligible for all the universities( I contacted queenmary as they asked for 666 but they said my result is fine), except for Durham which asks for 666. I emailed them and got their response:
"The entry requirements do state 666 is needed for the course. With that being said, we are unable to advise on what the outcome of an application would be without a full application. We take a holistic approach to all our applications, taking multiple factors into account to identify those with the greatest merit and potential. This includes any grades that have already been achieved as well as those which are predicted, in addition to the personal statement and reference."
I don't think I'm good enough for KCL and UCL as I see many people getting rejected for very high grades, and Durham is the best school I would have a chance of getting into.
I was wondering if I should apply now or later. I get another predicted in December, and I am pretty sure my total points are going to stay the same and my HL going to be 766. I want to apply now because I have been very stressed and anxious and want to get college apps over with, and because of my stress I am also worried that there's a small chance of getting my scores lower than the entry requirements of KCL and UCL. I have also heard about rolling admissions but I can't really find information about it anywhere. What should I do, and also what do you think about my uni list? Should I put more backup options?