I want to see racing back at Crystal Palace, hosts of the 1973 World CX championships.
But ideally hosting an event in central London would be visually appealing, so Regents Park or Hyde Park would be good. If they can fuck up the grass for dad rock bands, they can do it for a few Belgians.
To be fair, I reckon you could build a decent course at the Velopark and, by doing so, make it a regular venue for the London and Eastern Leagues.
I'd just love to see a more central London based course, as that would, I'd hope, get more people to attend.