I used drive the deal to buy our S-Max. Couldn’t have been easier. They are just a broker- they encourage dealers to give them their best price for any given model, then put the business their way. Presumably DTD take some commission from the dealer, but as a buyer, after the initial phone call to DTD you just speak to the dealership. Safe as houses. (well safe as buying a new car from a main dealer anyway)
I was well chuffed with the price I paid, £7000+ off list and £2000 less than the what car target price.
Only slight down side would be if you have a PX to get rid of, obviously they won’t be interested, but I just auctioned our old zafira.
Like you we looked around secondhand first, a similar spec 18 month old model was £2k more in our local ford dealers- no brainer.