In the short term, speak to Asdrubael or Wilco and tread moderately carefully.
With a bit of good grace and sensible 'in-character explanation', you might well get your gear back.
In the future, things will change. I've already changed it on the development server, and it's in testing right now (along with some other side-game stuff that I'm toying with). Basically, in the future, you will NOT immediately lose your vehicle license when you run someone over. You will still be wanted (of course - you killed someone!) but you will be expected to plead your case well to the officer who catches you. Things like whether you handed yourself in, or waited to be caught, may influence his decision. Things like whether you say "a troll player did it" in game, or "that suicidal fool was trying to get himself killed - there was nothing I could do to avoid him" (see the difference? There are no 'players' or 'trolls' in your local high street in RL, are there?).
Further to this, in the future if you ARE sent to jail with an outstanding Wanted for Vehicular Manslaughter, you'll lose your vehicle licences - but not your rebel licence. We want the penalties to fit the crime, and previously, they didn't, but that's changing.
IMO, Lewis's jailing you was pretty stiff, but maybe your explanation was crap and he simply didn't believe you, or thought you in some way responsible for the death? I find it hard to consider that it was murder (as in, malice aforethought, and all that)... and I expect that at worst, it should've been manslaughter - perhaps by your negligence at least in part (driving at a speed where you're able to stop in time, is the UK law - but obviously if someone leaps off the pavement this is next to impossible). By rights, I'd say 'fine' - and depending on your story quality, maybe even a token fine (you've been penalised enough by losing your vehicle licenses, without making it a whole lot worse). But then again, maybe you griefed the officer and insulted his mum? LOL Who knows... So - appeal this one with the Chief of Police, and see what arises.
At least you know it won't pan out quite like this again, and your reb licences will be safe... ish