Isn't this the case anyway? The whole point of one rep from each city filling one out... I'd say its fair for London to have 4 of the 10, the other 6 divided between the other cities.
If this isn't the case, I'd suggest LDN has a quali, and the rest of the uk have a separate quali for the other 6. I'm sure that the LDN teams that didn't make the top 4 would still qualify via the wild card.
These are all suggestions, it's ultimately Ale & co's decision and no one should try and influence this.
Don't bully us!