I just found out that CrystalVision bulbs are now available with the E1 marking which means they are road legal, which was not the case until recently. I'm already using these bulbs and just bought a spare pair from here:
https://www.amazon.co.uk/Philips-Crystal-H7 4300 K-12972CVUSM-E1 tested/dp/B01FJW6RR8/ref=sr_1_2?ie=UTF8&qid=1469720515&sr=8-2&keywords=philips+crystal+vision+h7
I was not sure if they were advertising it incorrectly because there is nothing on the packaging which shows that the bulbs are road legal, but sure enough there is an E1 marking under the bulbs. The older CrystalVisions had a marking which says "Not for use in EU / USA". I'm tempted to swap these new ones in to make sure I'm fully road legal, or at least check if the bulbs I bought last year already had the E1 marking.
More info on bulb markings here: http://www.ebay.co.uk/gds/How-to-Buy-the-Longest-Lasting-External-Car-Light-Bulb-/10000000177322146/g.html
Edit: Don't go buying these just yet because it looks like Philips might be cheating a bit here. The blue tinting on these new bulbs is a lot weaker than the older bulbs, and they have removed the "4300K" from the description on the packaging. I suspect the colour temperature is a lot lower which makes sense because that would allow for a higher light output, and that's probably why they are road legal and the older CrystalVisions are not. I'll swap out one of these at some point and compare to the older bulbs to see if I'm right about the colour temperature.
Another edit: more info here: http://www.powerbulbs.com/blog/2013/09/are-blue-car-bulbs-legal
Apparently halogen bulbs over 4200K are not road legal, so it's not just how they are tested that affects this. Or maybe that's part of the test; if the colour temp is over 4200K that's a fail (obviously not the case for HIDs).