I would contact the universities and enquire, as some courses may be more flexible than others
No University will commit to this before Results Day - simply because at this stage no Unis have any idea how the A level results will go, how many Firm applicants will make their offers, what spaces they then might have on any specific courses and which lower grades they might accept to fill them.
Medway, Reading, Brighton, and Hertfordshire
Medway and Herts are less competitive Unis overall than the other two BUT read my initial comment above - there are no guarantees about this. I'd advise you to simply pick the Insurance Uni that you prefer, and then work your socks off to get the grades you need for Kingston.