If you'd been hard on the gas with the front wheel up you wouldn't have been hit
First off very glad you're OK, sounds quite scary for all concerned!
In all seriousness sometimes there is pretty much nothing you can do, if you've managed 11 years in London without a prang, you're doing something right. Could you have done something different on this occasion? Hard to say from what you describe, it should as you say at least be pretty straightforward from an insurance point of view. Hope you get paid out.
In terms of what to buy next I can't convince myself it's any safer to cycle at all, I suppose you'll get fitter, but you'll be quieter, less visible, smaller, and generally wearing much less protective kit. Of course, you can cycle defensively but you seem to be doing that on the motorbike anyway.
What next? Well, with the changes to central London ULEZ requiring a Euro III compliant bike from 2020, you'll want something younger than the K4 (a 2007 onwards bike). I do like the look of the Yamaha MT range, be a dear, buy one with the insurance money and let me know if they're any good will you?
Jambo