To get their commission sooner rather than later I suspect DTD and other brokers hunt around for a dealer that has plenty of allocation left so that you get your car (and he gets his commission) sooner rather than later.
I doubt that DTD are bothered about waiting for their commission, as they do a huge amount of business. When I ordered from them (don't forget free delivery is included) they rang me and said, "You'll be hearing from the dealer closest to you on our books in the next couple of days." Exactly what happened, dealer down the road from me. I also know that they have links to a dealer in Kent and elsewhere, judging what has been posted on here.
The ability of brokers to get shorter build date waits than the rest of us in general does seem to suggest that they target dealerships with unused allocation, and they just so happen to use the nearest dealership to you that fits that criteria. Getting your VW via broker from your closest dealership may just be a coincidence. Perhaps your local dealership hasn’t sold anywhere near their allocation for GTI/GTD and the dealership is able to tap into that to get a relatively fast delivery.
On the other hand, perhaps the fleet side of any dealership (through which most broker deals are fulfilled) have few or no allocation considerations to make and so you can get one via these channels at the standard 12 week wait you would have for pretty much any VW you can currently order which has no allocation restrictions.
There are a lot of dealerships down South that seem to be more open to a sizeable discount than the Northern or Scottish dealerships going by what has been said on these forums (although good p/x prices seem to mitigate some of the lack of discount). Dealerships don’t give discounts away if they don’t have to. The new car market seems to be a lot healthier in the North/Scotland than the South right now, everyone down there seems open to giving a good discount to secure a sale, especially by taking on orders from a broker, so getting the broker deal fulfilled by your local dealer if you live down South isn’t to be unexpected.
I rang DTD up for a quote a while back and no dealership in the North East would supply. I’d have been getting mine from a Lancashire branch of the Lookers group if I’d have gone ahead.
All businesses are in it to make money, there is no bigger problem for a company that is making money than cash-flow so it stands to reason they’d want their money sooner rather than later, that’s just good business.