Without somebody else, independent, also willing to state the driver was being aggressive (whilst driving) you may not get them to do much more about his driving - that said, if he failed the attitude test with the police that turned up, it's a possibility. My guess, though, is that nothing will come of that.
I know some people will say you should insist the police do something - but the reality is, unless there's some other corroborating witness or evidence (potentially covered by road CCTV?), it's just a case of one person's word against another. And if it's a fairly simple accident, with no other (provable) factors, no damage elsewhere to road furniture, or anything like that, no aggravating factors, and no injury, and largely the police will probably not care.
Regardless of whether he's willing to admit liability, his insurers almost certainly will - unless they could get somebody else, independently to support his claim that it was your fault by brake testing him or something. I doubt his insurers will do more than pay lip service to whatever he tries to claim you did, and simply play the percentages and accept liability - it's quite difficult to do anything else when he's rear-ended you, unless, there's either form, or somebody unconnected willing to be a witness. So my guess, there, is that liability will be accepted by them.
As to what you do, well you're entitled to recompense for any loss - so if your own insurers are currently dealing with the claim - which you can choose to if you like - then your excess should be something that can be claimed back from the third party insurers.
edit: the other option - and a distinct and useful possibility, if his insurers 'fess up to liability, is deal directly with them. Excess shouldn't be a factor, they'll (like all insurers) try and minimise their costs (not unreasonably), but in my experience do so fairly, and reasonably quickly - if liability isn't questioned, it can be the quickest means of wrapping it all up, which should leave your NCB intact, since you wouldn't be claiming off your own insurance.
With somebody as arrogant as that, you may feel you don't want the hassle and are willing to let either legal protection (if available) or a claims handling company deal with it - although I'm not sure about whether there's many that provide things like scooters. But one thing to bear in mind - some, most, possibly all, make you (effectively) sign a credit agreement, and if (in the unlikely event the third party insurers refuse to accept liability, and / or refuse to cover the costs - inflated, or otherwise - from a claim handling company) the third party insurers don't cough up, you can be left with a bill. My advice - don't bother with a claim handling company, but do consider whether you can use, or pay the (what's normally small) fee for legal protection so somebody will be actively working on your behalf, rather than simply dealing with a claim, and hoping the third party insurers accept liability.
Also, consider if you have any injuries - I'm not about to advocate inventing anything - but all the same, if you have a stiff neck, or something like that, you may, legitimately, have some kind of whiplash injury - slow speed impacts tend to be often when they occur. Whilst that won't all be rosy for your own insurance costs going forward, if there's something that deserves a claim, and a very deserving third party to claim from, you may feel that you should ensure you're not being short-changed in terms of your recompense for the incident. My advice - get what your due - but bear this in mind - non fault claims still will have a bearing on your insurance costs, going forward - the larger the claim, the more the impact - even if your NCB is ultimately unaffected / reinstated. It's likely the calculation for your base premium will be affected, and your NCB is just a discount that then gets applied once your base premium is calculated. So non-fault claims, especially significant ones, perhaps including personal injury, can have some bearing for some years to come - worth considering when you're young, and relatively inexperienced, and insurance costs are already high.
So I'd recommend ensuring you're not out of pocket in terms of repair or replacement, but keeping a lid on it there, tempting though it may be to ensure that every single, possible thing you could claim for, gets claimed for from such an arse.
As to how you dealt with it - kudos - whether because tired, or just having pragmatic presence of mind - being calm, not getting involved in argy-bargy, and saying nothing more than the bare minimum tends to be a good approach - so well done there.
scooter is being collected monday morning and i will get it back sometime in january apparently. they can keep it as long as they want... im loving riding this bike..
